1. Introduction
2. JCL Syntax
Syntax Rules
Job Statement
Accounting Information parameter :
Programmer’s Name :
MSGLEVEL parameter :
TheMSGCLASS parameter :
The Class Parameter :
The PRTY parameter
The TIME Parameter
The REGION parameter
The ADDRSPC parameter
The NOTIFY parameter
The RESTART parameter
The TYPRUN parameter
3. The EXEC statement
The REGION Parameter
The TIME parameter
The ADDRSPC parameter
The ACCT Parameter
The PARM Parameter
The COND Parameter
4. The DD statement
The DSN Parameter
The DISP Parameter
The UNIT Parameter
The VOL Parameter
The SPACE Parameter
The LABEL Parameter
The DCB Parameter
Instream Data
The SYSOUT Parameter
Concatenation
DUMMY Parameter
The JOBLIB DD Statement
The STEPLIB STATEMENT
STORAGE DUMP
5. Procedure
SYMBOLIC PARAMETERS & SYMBOLIC OVERRIDES
THE PROC STATEMENT
IN-STREAM PROCEDURES
6. Utility
IEFBR14 UTILITY
IEBGENER UTILITY
SORT UTILITY
Monday, March 8, 2010
1. Introduction
Need of JCL
1. Introduction
JCL is a language in which the users of a computer systems describes to that system the requirements of their jobs.
• Provides a primary interface between user and the JES.
• Used to perform batch mode processing under MVS.
Within a job, JCL provides the specification necessary for MVS to process the job.
Specifications of a job are :
• User identity
• Data file identity
• Resource requirement
• Error handling
Need of JCL
• Request execution of program under MVS environment
• Sets the requirement for a job
Back to JCL Index
Back to home page
1. Introduction
JCL is a language in which the users of a computer systems describes to that system the requirements of their jobs.
• Provides a primary interface between user and the JES.
• Used to perform batch mode processing under MVS.
Within a job, JCL provides the specification necessary for MVS to process the job.
Specifications of a job are :
• User identity
• Data file identity
• Resource requirement
• Error handling
Need of JCL
• Request execution of program under MVS environment
• Sets the requirement for a job
Back to JCL Index
Back to home page
2. JCL Syntax
Syntax Rules
General JCL command format
//name operation parameter1,parameter2 Comments
where;
name : is not to exceed 8 characters
operation : generally begins in column 12
parameter : generally begins in column 17
comments : are separated from the parameters by a blank
Parameters are broadly classified into 2 categories viz. Positional and Keyword.
A positional parameter is identified by its position relative to other parameters in the operand field.
Rule 1 : All positional parameters are coded first in the operand field and in their proper sequence.
e.g. : p1,p2,p3
p1,p3,p2 illegal because they are not in sequence.
A keyword parameter is identified by a keyword followed by an equal sign (=) and variable information.
Rule 2 : A keyword parameter follows positional parameter and can be coded in any order.
e.g. : p1,p2,p3,k1=,k2=,k3=
p1,p2,p2,k3=,k2=,k1=
Both are valid.
Note : All parameters are separated by commas with no intervening spaces.
Rule 3 : The absence of positional parameter is noted by a comma(,) coded in its place, except for the last or remainder of the positional parameter are not present. The placeholder commas do not need to be coded.
e.g. : p1,,p3,k1=,k2=,k3= place holder comma required
p1,k1=,k2=,k3=
Rule 4 : Both positional parameters and variable information for keyword parameters may be composed of subparameters. The subparameters may be either positional or keyword. Subparameters must be coded as a list. The list must be enclosed in paranthesis unless only one subparameter is coded. When only one subparameter is coded the paranthesis are optional.
e.g : p1,(sp1,sp2),p3,k1=(sk1,sk2),k2=,k3=
p1,(sp1),p3,k1=(sk1),k2=,k3=
or p1,sp1,p3,k1=sk1,k2=,k3=
Rules for continuation : The JCL statement can be continued in a simple way. The statement must be interrupted at a comma. This means that the last valid character of the line must be a comma followed by atleast one blank. Then the statement can be continued into the next line by coding two slashes at the beginning of the line and continuing the parameter field starting anywhere between positions 4 and 16 (4 and 16 included). Note that the comma which indicates continuation, is not an extraneous character but part of the statement.
//dd1 dd dsn=da0001t.empfile,disp=(new,catalg,delete),
// unit=sysda,space=(trk,(5,1)),dcb=(lrecl=80,recfm=fb,blksize=800)
//dd1 dd dsn=da0001t.empfile,disp=(new,catalg,delete),
// unit=sysda,space=(trk,(5,
// 1)),dcb=(lrecl=80,recfm=fb,blksize=800)
//
Eg. 2.1 Examples of valid continuation
Job Statement
The job statement identifies job to the O/S with the job name operand.
The format of the JOB statement is :
//jobname JOB parameters
Note that jobname cannot exceed 8 characters and is usually the userid (loginid)
//da0001ta JOB parameters
Loginid is generally 7 characters, so you need to add a suffix lest the system prompts you to enter the character when a job is submitted to the system for execution.
When a job is submitted to the system, a job number is also assigned so that the job can be further identified. This way jobs with the same name can be uniquely identified. Jobs with the same name cannot execute simultaneously. If several jobs with the same name are submitted they execute sequentially even if additional jobs could be executing. Jobs waiting to run because of this time conflict are shown in hold status.
Remark : 1 A JOB statement must be at the beginning of every job submitted to the system for execution.
2 A JOB statement must have a name. The absence of a jobname will result in a JCL error.
The rest of the JOB statement contains postional parameters followed by keyword.
Accounting Information parameter :
It is a positional parameter. If present (it normally is), it must be the first in the parameter field. It can have a maximum of 142 characters (including parenthesis and commas but not apostrophes) . It is used to tie the resources used by the job to the appropriate account.
//jobname JOB ([account-number][,additional-accounting-information]),parameters
The account-number is an alphanumeric field from 1 to 4 characters long (many installations permit the use of more than 4 characters.
Additional-accounting-information is installation dependent. Many of the fields are not very important and are not often used. Note that except for the account number, all other subparameters can be supplied through the /*JOBPARM JES2 control statement. (JES2 control statements are not covered in this book, refer to IBM Manual.
e.g :
//da0001ta JOB LA2719,parameters
LA2719 is the account number for the training dept. This varies from project to project. Therefore, consult the right person.
If any portion of the field contains a special character other than a “,” (comma) or a “-“ (hyphen), the portion must be enclosed in apostrophes. If an ampersand or quotes is used in the accounting field, code two consecutive ampersands or quotes.
e.g. :1
//da0001ta JOB ‘LA2719,TRG’
or //da0001ta JOB (LA2719,TRG)
e.g. :2
//da0001ta JOB (LA2719,’P&&G’)
The system assumes a single ampersand.
Remark: An installation has the option of making the account number mandatory and most installations do. If so, its absence will cause a JCL error.
If the account number is incorrectly specified, in this case its not JCL error. However when job is submitted to the system for execution, we get the message JOB NOT RUN in the sysout.
Programmer’s Name :
Following the accounting information parameter, another positional parameter, the programmer’s name can be coded. The installation determines if this parameter is required or not. If required, it must be coded immediately after the accounting information, and its omission will cause a JCL error. The programmer’s name cannot exceed 20 characters. If it contains any special characters other than a hyphen and a period in the middle or the beginning (but not at the end) of the name, the name must be enclosed in apostrophes. The apostrophes are not added to the length of the name. If a name contains an apostrophe (e.g., D’COSTA), two apostrophes must be coded. They count as one character in the length of the name.
e.g. : 1
//da0001ta JOB LA2719,Pai,parameters
e.g. : 2
//da0001ta JOB LA2719,’D’’COSTA’,parameters
Note : Accounting information and Programmer’s name are the only two positional parameters in the JOB statement, what follows after that are keyword parameters.
MSGLEVEL parameter :
This parameter specifies whether the submitted JCL and/or JCL-related messages should be shown on the job’s output.
General syntax
MSGLEVEL=([jcl][,messages]) Keyword parameter
Jcl - 0, 1, or 2
0 - only the JOB statement will be shown
1 - All JCL will be shown
• instream
• expanded cataloged procedures
• symbolic parameter substitutions
2 - All JCL will be shown, but not expanded procedure listing.
Messages – 0 or 1
0 - No messages will be shown i.e information about step completion.
1 – All messages will be shown viz allocation and termination messages.
The messages subparameter can be thought of as On (1) or Off (0) .
Remark:
1. If the entire parameter or either of the two fields is omitted, an installation-defined default is assumed.
MSGLEVEL=1 ------------------MSGLEVEL=(1,default)
MSGLEVEL=(,1) ------------------MSGLEVEL=(default,1)
Parameter omitted ------------------ MSGLEVEL=(default,default)
2. If the job encounter an ABEND failure, the second field always defaults to 1 even if coded as 0
TheMSGCLASS parameter :
This parameter assigns a sysout class to the Job log. The job log consists of what is what is known as system or JES datasets:
• JES2 or JES3 log
• JCL and its associated messages
• Allocation and Termination messages
MSGCLASS - indicates the format of output
- specifies output class for
job log (collection of all operations)
list (collection of all printed output like compiled listing)
General Syntax
MSGCLASS=class Keyword parameter
Class - A character from A to Z or a number from 0 to 9 (in all 36 classes)
MSGLEVEL parameter indicates whether or not one wishes to print the JCL statements and allocation messages. The MSGLEVEL can save paper. After a job is debugged, there may be no need to print all the JCL and allocation messages each time it runs. To reduce printing to a minimum, one may wish to MSGLEVEL=(0,0).
All datasets to be printed must have a class. This is normally called the output class, sysout class or message class. Sysout datasets created by the executing programs are assigned a class by the SYSOUT DISTINCT statement. After the job terminates, the sysout datasets, which are saved on the spool pack , will be selected and printed by a JES2 or JES3 component called a printer. There are several printers available, and each one is assigned one or more sysout classes (from 1 t0 36). The sysout class can be thought of as a print-scheduling class.
Remark : If the MSGCLASS parameter is omitted, an installation-defined default will be used.
The Class Parameter :
This parameter assigns a class to a job.
General Syntax
CLASS=jobclass Keyword parameter
Jobclass – A letter from A to Z or a number from 0 to 9 ( in all 36 classes)
The jobclass affects job’s processing in these ways :
• When job is submitted, it is placed in an input queue where it waits to be executed. Queues can be thought of as waiting lines for jobs. Each job class has its own input queue
• Job waits in the input queue until it is selected by an initiator to be processed. Each initiator is set to a list of job classes that it can select from.
Simply put Jobclass identifies the nature of the job
- short running or long running
- resource utilization
Each installation group jobs that have like characterstics into classes. By segregrating jobs with similar characterstics, an installation can maintain a good mix of the jobs running at a given moment. This maintains system throughput and efficient use of resources.
Let us look at the sample table below
Class Code Run Time (in minutes) Tape Disk Production Test
1 5 X X X
2 >5 X X X
A 5 X X X
B <5 X X X
C >5 X X X
Table 2.1
In the sample table, the job classes were separated by
- Production vs Test
- Tape vs disk
- expected run time
The example shows some of the characteristics an installation may look at, but certainly not all. Also, resources used by a job may be critical at one installation, but not at another. What is important is that one should follow installation’s standard.
For e.g. Suppose the default Class is A
This Job statement
//DA0001TA JOB LA2719,PCS,MSGCLASS=A,MSGLEVEL=(1,1)
is equivalent to
//DA0001TA JOB LA2719,PCS,MSGCLASS=A,MSGLEVEL=(1,1),CLASS=A
Remark :
Frequently, installations develop a testing class structure that favors short-running jobs with minimal resource requirements and penalize long-running jobs with heavy resource demands. This is achieved by assigning the class used by trivial jobs to many initiators and class used by heavy jobs to few. To keep people honest, the CLASS parameter in a testing environment is often tied to several other parameters such as TIME,PRTY, REGION, etc. For example, a job coding CLASS=A can be given TIME=(0,5),PRTY=6. Note that the values assigned to these parameters is not shown in the output. However, if any of these parameters were coded in the JOB statement, they would be ignored.
Most installation assigns a default job class if the Class parameter is omitted.
The PRTY parameter
This parameter determines the scheduling priority of a job in relation to other jobs in the job input queue of the same class.
General Syntax
PRTY=priorty - keyword parameter
Priorty – a number from 0 to 15 for JES2 or 0 to 14 for JES3
The PRTY parameter is used to define the job’s input class selection priority :
• The higher the number, the better (greater) the priority
• The PRTY parameter simply controls the job’s position in the input queue. It has no affect on the job’s performance.
• Jobs with higher priorities will be selected before job’s will lower priority
• A job’s priority does not affect its performance. Once the job is selected for execution, the priority function is finished.
• Two jobs having same job class and same priority will be executed in sequence
Comparing the PRTY parameter of two jobs belonging to different classes is meaningless.
Remark :
This parameter is of seldom use in a testing environment. Since high priorty would be used by practically all users negating the very purpose the parameter,. Therefore, in most installation the PRTY, whether coded or not, will default to an installation-defined value or will be supplied by the CLASS parameter.
The TIME Parameter
This parameter specifies the total amount of CPU time that all steps in a job can use collectively.
General Syntax
TIME=([minutes][,seconds] | [1440]) keyword parameter
minutes - a number from 1 to 1439
seconds - a number from 1 to 59
1440 - The job will not be timed for CPU. It was also not “time out” (S522 ABEND failure) when a single wait state exceeds the installation-defined limit (often 10 to 20 minutes). Note that TIME=1440 is rarely used, and most installation disallow its use in a testing environment. TIME=1440 should be used by an on-line system like CICS OR ADS/O.
When the TIME parameter is omitted, an installation-defined default will be used. This default is usually very high and unlikely to cause an S322 ABEND failure unless the program goes into an endless loop.
If the TIME parameter is also coded in the JOB statement, both will be in effect and either can cause a S322 ABEND failure. It is not advisable to use them both.
CPU time is the amount of time that the computer devoted to the job after it was selected for processing. It is not the amount of time it was in the machine.
TIME parameter puts an upper limit on the amount of CPU time that a job may use.
e.g : TIME=(3,20).
All the steps in the job are allowed collectively 3 minutes and 20 seconds of CPU time. If this amount is exceeded, the result will be a S322 ABEND failure.
If the TIME parameter is coded using only minutes, seconds defaults to zero. For example, TIME=5 is the same as TIME=(6,0).
If the TIME parameter is coded using only seconds, minutes defaults to zero. For example, TIME=(,6) is the same as TIME=(0,6).
The TIME parameter is intended almost exclusively for a testing environment and should be coded to preempt the program going into CPU loop.
The TIME parameter can also be supplied by the CLASS parameter. When the TIME parameter is omitted and the CLASS parameter does not supply it, the job will not be timed for CPU time. However each step will be individually timed (TIME parameter at EXEC statement or its installation-defined default), unless it contains TIME=1440.
Remark:
It is possible for a job to get more CPU time than that is specified in the TIME parameter by a maximum 10.5 seconds. This is due to the fact that the system checks for violations every 10.5 seconds.
The REGION parameter
This parameter specifies the limit of available storage for each of the steps in the job within the job’s address space. i.e., the amount of storage the job is allocated. Or, in other words, it specfies the amount of storage needed by the step (within the job) with the highest storage requirements.
General Syntax
REGION=value{K|M} keyword parameter
Value – 1 to 2096128 if K (1024 bytes) is used. It should be an even number, it will be rounded to the next higher even number.
Value – 1 to 2047 if M (1024K or 1048576 bytes) is used. M is not available to MVS/SP, only to MVS/XA and MVS/ESA
When a job is selected by an initiator for execution, it is given an address space of 16 MB ( minus what MVS/SP uses) .Incase of MVS/XA, job is given an address space of 2GB. And all of it is available to the job’s steps. However a step normally requires only a small fraction of this huge storage, below the 16M line. An ordinary COBOL or any other language program seldom needs more than 1000k. This is normally what the value in the REGION parameter represents in the installations. Few jobs like CICS, IMS, DB2 need storage above the 16M line. An ordinary batch job seldom has such high requirements and, as a result confined to storage below the 16M line. Storage availability below this line varies in different installations, but is generally around 8MB in MVS/SP and around 9 MB in MVS/XA. Storage above the 16M line can be acquired by coding a value higher than 16M. However, it may be restricted by the installation to only those jobs that need it.
E.g 1.
Assume REGION=1000K was coded in the JOB statement. All the steps in the job are limited to this value. If more storage is needed, the usual result is S878 or S80A or S804 ABEND failure. If one of these failures occurs, the user must increase the value in the REGION parameter.
E.g 2.
REGION=10M
When the amount of storage requested in the REGION parameter is higher than the address space can provide, an S822 ABEND failure will result.
Note that for job run under MVS/SP, the entire address space is limited to 16M, of which usually less than 8M is available to the user. In case of MVS/XA, the entire address space is limited to 2G, of which usually around 9M is available to the user.
E.g 3.
REGION=0K (or 0M) is coded the entire address space except for those areas used by MVS/SP (or MVS/XA) is available.
The ADDRSPC parameter
This parameter specifies if the job will use real or virtual storage.
General syntax
ADDRSPC={VIRT|REAL}
VIRT – The REGION will be virtual storage and is the default
REAL – The REGION will be real storage.
Remark:
This is the rarely used parameter because of the default. Note that ADDRSPC=REAL is a parameter that is disallowed in practically all installation because it can cause serious performance problems for other jobs.
The NOTIFY parameter
This parameter informs a TSO user when his or his job terminates.
General Syntax
NOTIFY=userid keyword parameter
Userid – A name from 1 to 7 character, identifying a valid TSO user.
E.g NOTIFY=DA0001T
If coded, a message will appear on the user’s TSO terminal indicating if the job abended or got a JCL error. If the job terminates while the user was logged off, the message will appear when the user logs on. If the NOTIFY parameter is omitted, no message will appear when the job terminates.
Remark :
You can also code NOTIFY=&SYSUID instead of your userid.
The RESTART parameter
This parameter requests that a job begin its execution with a step other than the first one.
General Syntax
RESTART={stepname|procexec.stepname| *} keyword parameter
Stepname – The name of the step where execution is to begin.
Procexec.stepname – The name of the EXEC statement invoking a procedure and the name of the step within the procedure where execution is to begin
Note : Procedures will be covered on day 4.
* - indicates that execution of the job is to begin with the first step and is the default.
Things to avoid :
• Duplicate name for EXEC statements invoking procedure. If RESTART=procsexec.stepname is used, the first procexec found will be used.
• Duplicate stepnames within procedure. If RESTART=procsexec.stepname is used, the first stepname within procexec found will be used.
• Duplicate stepnames. If RESTART=stepname is used, the first stepname found will be used.
• EXEC statements (invoking procedures or any step) without names. No restart is possible
• Creating and passing temporary datasets. Such datasets are always deleted by the time the job terminates and, therfore unavailable for restarting.
• Creating and passing nontemporary datasets. If such a dataset is not received and assigned a permanent disposition, Job Termination will delete it, making restart impossible
The TYPRUN parameter
This parameter requests special processing for the job.
General Syntax
TYPRUN={HOLD|JCLHOLD|SCAN|COPY} keyword parameter
HOLD - Job will held (and not executed temporarily) until the operator uses a command to release. A job will be held in the input queue only if syntactically correct
JCLHOLD (JES2 only) – Job will held (and not executed) until the operator uses a command to release it. Note the job will be held in queue if it is syntactically incorrect. Rarely used
SCAN – Job will be scanned for all syntactical JCL errors but will not execute.
COPY (JES2 only)- Job will be printed. No execution and no syntax checking takes place. Rarely used.
Back to JCL Index
Back to home page
General JCL command format
//name operation parameter1,parameter2 Comments
where;
name : is not to exceed 8 characters
operation : generally begins in column 12
parameter : generally begins in column 17
comments : are separated from the parameters by a blank
Parameters are broadly classified into 2 categories viz. Positional and Keyword.
A positional parameter is identified by its position relative to other parameters in the operand field.
Rule 1 : All positional parameters are coded first in the operand field and in their proper sequence.
e.g. : p1,p2,p3
p1,p3,p2 illegal because they are not in sequence.
A keyword parameter is identified by a keyword followed by an equal sign (=) and variable information.
Rule 2 : A keyword parameter follows positional parameter and can be coded in any order.
e.g. : p1,p2,p3,k1=,k2=,k3=
p1,p2,p2,k3=,k2=,k1=
Both are valid.
Note : All parameters are separated by commas with no intervening spaces.
Rule 3 : The absence of positional parameter is noted by a comma(,) coded in its place, except for the last or remainder of the positional parameter are not present. The placeholder commas do not need to be coded.
e.g. : p1,,p3,k1=,k2=,k3= place holder comma required
p1,k1=,k2=,k3=
Rule 4 : Both positional parameters and variable information for keyword parameters may be composed of subparameters. The subparameters may be either positional or keyword. Subparameters must be coded as a list. The list must be enclosed in paranthesis unless only one subparameter is coded. When only one subparameter is coded the paranthesis are optional.
e.g : p1,(sp1,sp2),p3,k1=(sk1,sk2),k2=,k3=
p1,(sp1),p3,k1=(sk1),k2=,k3=
or p1,sp1,p3,k1=sk1,k2=,k3=
Rules for continuation : The JCL statement can be continued in a simple way. The statement must be interrupted at a comma. This means that the last valid character of the line must be a comma followed by atleast one blank. Then the statement can be continued into the next line by coding two slashes at the beginning of the line and continuing the parameter field starting anywhere between positions 4 and 16 (4 and 16 included). Note that the comma which indicates continuation, is not an extraneous character but part of the statement.
//dd1 dd dsn=da0001t.empfile,disp=(new,catalg,delete),
// unit=sysda,space=(trk,(5,1)),dcb=(lrecl=80,recfm=fb,blksize=800)
//dd1 dd dsn=da0001t.empfile,disp=(new,catalg,delete),
// unit=sysda,space=(trk,(5,
// 1)),dcb=(lrecl=80,recfm=fb,blksize=800)
//
Eg. 2.1 Examples of valid continuation
Job Statement
The job statement identifies job to the O/S with the job name operand.
The format of the JOB statement is :
//jobname JOB parameters
Note that jobname cannot exceed 8 characters and is usually the userid (loginid)
//da0001ta JOB parameters
Loginid is generally 7 characters, so you need to add a suffix lest the system prompts you to enter the character when a job is submitted to the system for execution.
When a job is submitted to the system, a job number is also assigned so that the job can be further identified. This way jobs with the same name can be uniquely identified. Jobs with the same name cannot execute simultaneously. If several jobs with the same name are submitted they execute sequentially even if additional jobs could be executing. Jobs waiting to run because of this time conflict are shown in hold status.
Remark : 1 A JOB statement must be at the beginning of every job submitted to the system for execution.
2 A JOB statement must have a name. The absence of a jobname will result in a JCL error.
The rest of the JOB statement contains postional parameters followed by keyword.
Accounting Information parameter :
It is a positional parameter. If present (it normally is), it must be the first in the parameter field. It can have a maximum of 142 characters (including parenthesis and commas but not apostrophes) . It is used to tie the resources used by the job to the appropriate account.
//jobname JOB ([account-number][,additional-accounting-information]),parameters
The account-number is an alphanumeric field from 1 to 4 characters long (many installations permit the use of more than 4 characters.
Additional-accounting-information is installation dependent. Many of the fields are not very important and are not often used. Note that except for the account number, all other subparameters can be supplied through the /*JOBPARM JES2 control statement. (JES2 control statements are not covered in this book, refer to IBM Manual.
e.g :
//da0001ta JOB LA2719,parameters
LA2719 is the account number for the training dept. This varies from project to project. Therefore, consult the right person.
If any portion of the field contains a special character other than a “,” (comma) or a “-“ (hyphen), the portion must be enclosed in apostrophes. If an ampersand or quotes is used in the accounting field, code two consecutive ampersands or quotes.
e.g. :1
//da0001ta JOB ‘LA2719,TRG’
or //da0001ta JOB (LA2719,TRG)
e.g. :2
//da0001ta JOB (LA2719,’P&&G’)
The system assumes a single ampersand.
Remark: An installation has the option of making the account number mandatory and most installations do. If so, its absence will cause a JCL error.
If the account number is incorrectly specified, in this case its not JCL error. However when job is submitted to the system for execution, we get the message JOB NOT RUN in the sysout.
Programmer’s Name :
Following the accounting information parameter, another positional parameter, the programmer’s name can be coded. The installation determines if this parameter is required or not. If required, it must be coded immediately after the accounting information, and its omission will cause a JCL error. The programmer’s name cannot exceed 20 characters. If it contains any special characters other than a hyphen and a period in the middle or the beginning (but not at the end) of the name, the name must be enclosed in apostrophes. The apostrophes are not added to the length of the name. If a name contains an apostrophe (e.g., D’COSTA), two apostrophes must be coded. They count as one character in the length of the name.
e.g. : 1
//da0001ta JOB LA2719,Pai,parameters
e.g. : 2
//da0001ta JOB LA2719,’D’’COSTA’,parameters
Note : Accounting information and Programmer’s name are the only two positional parameters in the JOB statement, what follows after that are keyword parameters.
MSGLEVEL parameter :
This parameter specifies whether the submitted JCL and/or JCL-related messages should be shown on the job’s output.
General syntax
MSGLEVEL=([jcl][,messages]) Keyword parameter
Jcl - 0, 1, or 2
0 - only the JOB statement will be shown
1 - All JCL will be shown
• instream
• expanded cataloged procedures
• symbolic parameter substitutions
2 - All JCL will be shown, but not expanded procedure listing.
Messages – 0 or 1
0 - No messages will be shown i.e information about step completion.
1 – All messages will be shown viz allocation and termination messages.
The messages subparameter can be thought of as On (1) or Off (0) .
Remark:
1. If the entire parameter or either of the two fields is omitted, an installation-defined default is assumed.
MSGLEVEL=1 ------------------MSGLEVEL=(1,default)
MSGLEVEL=(,1) ------------------MSGLEVEL=(default,1)
Parameter omitted ------------------ MSGLEVEL=(default,default)
2. If the job encounter an ABEND failure, the second field always defaults to 1 even if coded as 0
TheMSGCLASS parameter :
This parameter assigns a sysout class to the Job log. The job log consists of what is what is known as system or JES datasets:
• JES2 or JES3 log
• JCL and its associated messages
• Allocation and Termination messages
MSGCLASS - indicates the format of output
- specifies output class for
job log (collection of all operations)
list (collection of all printed output like compiled listing)
General Syntax
MSGCLASS=class Keyword parameter
Class - A character from A to Z or a number from 0 to 9 (in all 36 classes)
MSGLEVEL parameter indicates whether or not one wishes to print the JCL statements and allocation messages. The MSGLEVEL can save paper. After a job is debugged, there may be no need to print all the JCL and allocation messages each time it runs. To reduce printing to a minimum, one may wish to MSGLEVEL=(0,0).
All datasets to be printed must have a class. This is normally called the output class, sysout class or message class. Sysout datasets created by the executing programs are assigned a class by the SYSOUT DISTINCT statement. After the job terminates, the sysout datasets, which are saved on the spool pack , will be selected and printed by a JES2 or JES3 component called a printer. There are several printers available, and each one is assigned one or more sysout classes (from 1 t0 36). The sysout class can be thought of as a print-scheduling class.
Remark : If the MSGCLASS parameter is omitted, an installation-defined default will be used.
The Class Parameter :
This parameter assigns a class to a job.
General Syntax
CLASS=jobclass Keyword parameter
Jobclass – A letter from A to Z or a number from 0 to 9 ( in all 36 classes)
The jobclass affects job’s processing in these ways :
• When job is submitted, it is placed in an input queue where it waits to be executed. Queues can be thought of as waiting lines for jobs. Each job class has its own input queue
• Job waits in the input queue until it is selected by an initiator to be processed. Each initiator is set to a list of job classes that it can select from.
Simply put Jobclass identifies the nature of the job
- short running or long running
- resource utilization
Each installation group jobs that have like characterstics into classes. By segregrating jobs with similar characterstics, an installation can maintain a good mix of the jobs running at a given moment. This maintains system throughput and efficient use of resources.
Let us look at the sample table below
Class Code Run Time (in minutes) Tape Disk Production Test
1 5 X X X
2 >5 X X X
A 5 X X X
B <5 X X X
C >5 X X X
Table 2.1
In the sample table, the job classes were separated by
- Production vs Test
- Tape vs disk
- expected run time
The example shows some of the characteristics an installation may look at, but certainly not all. Also, resources used by a job may be critical at one installation, but not at another. What is important is that one should follow installation’s standard.
For e.g. Suppose the default Class is A
This Job statement
//DA0001TA JOB LA2719,PCS,MSGCLASS=A,MSGLEVEL=(1,1)
is equivalent to
//DA0001TA JOB LA2719,PCS,MSGCLASS=A,MSGLEVEL=(1,1),CLASS=A
Remark :
Frequently, installations develop a testing class structure that favors short-running jobs with minimal resource requirements and penalize long-running jobs with heavy resource demands. This is achieved by assigning the class used by trivial jobs to many initiators and class used by heavy jobs to few. To keep people honest, the CLASS parameter in a testing environment is often tied to several other parameters such as TIME,PRTY, REGION, etc. For example, a job coding CLASS=A can be given TIME=(0,5),PRTY=6. Note that the values assigned to these parameters is not shown in the output. However, if any of these parameters were coded in the JOB statement, they would be ignored.
Most installation assigns a default job class if the Class parameter is omitted.
The PRTY parameter
This parameter determines the scheduling priority of a job in relation to other jobs in the job input queue of the same class.
General Syntax
PRTY=priorty - keyword parameter
Priorty – a number from 0 to 15 for JES2 or 0 to 14 for JES3
The PRTY parameter is used to define the job’s input class selection priority :
• The higher the number, the better (greater) the priority
• The PRTY parameter simply controls the job’s position in the input queue. It has no affect on the job’s performance.
• Jobs with higher priorities will be selected before job’s will lower priority
• A job’s priority does not affect its performance. Once the job is selected for execution, the priority function is finished.
• Two jobs having same job class and same priority will be executed in sequence
Comparing the PRTY parameter of two jobs belonging to different classes is meaningless.
Remark :
This parameter is of seldom use in a testing environment. Since high priorty would be used by practically all users negating the very purpose the parameter,. Therefore, in most installation the PRTY, whether coded or not, will default to an installation-defined value or will be supplied by the CLASS parameter.
The TIME Parameter
This parameter specifies the total amount of CPU time that all steps in a job can use collectively.
General Syntax
TIME=([minutes][,seconds] | [1440]) keyword parameter
minutes - a number from 1 to 1439
seconds - a number from 1 to 59
1440 - The job will not be timed for CPU. It was also not “time out” (S522 ABEND failure) when a single wait state exceeds the installation-defined limit (often 10 to 20 minutes). Note that TIME=1440 is rarely used, and most installation disallow its use in a testing environment. TIME=1440 should be used by an on-line system like CICS OR ADS/O.
When the TIME parameter is omitted, an installation-defined default will be used. This default is usually very high and unlikely to cause an S322 ABEND failure unless the program goes into an endless loop.
If the TIME parameter is also coded in the JOB statement, both will be in effect and either can cause a S322 ABEND failure. It is not advisable to use them both.
CPU time is the amount of time that the computer devoted to the job after it was selected for processing. It is not the amount of time it was in the machine.
TIME parameter puts an upper limit on the amount of CPU time that a job may use.
e.g : TIME=(3,20).
All the steps in the job are allowed collectively 3 minutes and 20 seconds of CPU time. If this amount is exceeded, the result will be a S322 ABEND failure.
If the TIME parameter is coded using only minutes, seconds defaults to zero. For example, TIME=5 is the same as TIME=(6,0).
If the TIME parameter is coded using only seconds, minutes defaults to zero. For example, TIME=(,6) is the same as TIME=(0,6).
The TIME parameter is intended almost exclusively for a testing environment and should be coded to preempt the program going into CPU loop.
The TIME parameter can also be supplied by the CLASS parameter. When the TIME parameter is omitted and the CLASS parameter does not supply it, the job will not be timed for CPU time. However each step will be individually timed (TIME parameter at EXEC statement or its installation-defined default), unless it contains TIME=1440.
Remark:
It is possible for a job to get more CPU time than that is specified in the TIME parameter by a maximum 10.5 seconds. This is due to the fact that the system checks for violations every 10.5 seconds.
The REGION parameter
This parameter specifies the limit of available storage for each of the steps in the job within the job’s address space. i.e., the amount of storage the job is allocated. Or, in other words, it specfies the amount of storage needed by the step (within the job) with the highest storage requirements.
General Syntax
REGION=value{K|M} keyword parameter
Value – 1 to 2096128 if K (1024 bytes) is used. It should be an even number, it will be rounded to the next higher even number.
Value – 1 to 2047 if M (1024K or 1048576 bytes) is used. M is not available to MVS/SP, only to MVS/XA and MVS/ESA
When a job is selected by an initiator for execution, it is given an address space of 16 MB ( minus what MVS/SP uses) .Incase of MVS/XA, job is given an address space of 2GB. And all of it is available to the job’s steps. However a step normally requires only a small fraction of this huge storage, below the 16M line. An ordinary COBOL or any other language program seldom needs more than 1000k. This is normally what the value in the REGION parameter represents in the installations. Few jobs like CICS, IMS, DB2 need storage above the 16M line. An ordinary batch job seldom has such high requirements and, as a result confined to storage below the 16M line. Storage availability below this line varies in different installations, but is generally around 8MB in MVS/SP and around 9 MB in MVS/XA. Storage above the 16M line can be acquired by coding a value higher than 16M. However, it may be restricted by the installation to only those jobs that need it.
E.g 1.
Assume REGION=1000K was coded in the JOB statement. All the steps in the job are limited to this value. If more storage is needed, the usual result is S878 or S80A or S804 ABEND failure. If one of these failures occurs, the user must increase the value in the REGION parameter.
E.g 2.
REGION=10M
When the amount of storage requested in the REGION parameter is higher than the address space can provide, an S822 ABEND failure will result.
Note that for job run under MVS/SP, the entire address space is limited to 16M, of which usually less than 8M is available to the user. In case of MVS/XA, the entire address space is limited to 2G, of which usually around 9M is available to the user.
E.g 3.
REGION=0K (or 0M) is coded the entire address space except for those areas used by MVS/SP (or MVS/XA) is available.
The ADDRSPC parameter
This parameter specifies if the job will use real or virtual storage.
General syntax
ADDRSPC={VIRT|REAL}
VIRT – The REGION will be virtual storage and is the default
REAL – The REGION will be real storage.
Remark:
This is the rarely used parameter because of the default. Note that ADDRSPC=REAL is a parameter that is disallowed in practically all installation because it can cause serious performance problems for other jobs.
The NOTIFY parameter
This parameter informs a TSO user when his or his job terminates.
General Syntax
NOTIFY=userid keyword parameter
Userid – A name from 1 to 7 character, identifying a valid TSO user.
E.g NOTIFY=DA0001T
If coded, a message will appear on the user’s TSO terminal indicating if the job abended or got a JCL error. If the job terminates while the user was logged off, the message will appear when the user logs on. If the NOTIFY parameter is omitted, no message will appear when the job terminates.
Remark :
You can also code NOTIFY=&SYSUID instead of your userid.
The RESTART parameter
This parameter requests that a job begin its execution with a step other than the first one.
General Syntax
RESTART={stepname|procexec.stepname| *} keyword parameter
Stepname – The name of the step where execution is to begin.
Procexec.stepname – The name of the EXEC statement invoking a procedure and the name of the step within the procedure where execution is to begin
Note : Procedures will be covered on day 4.
* - indicates that execution of the job is to begin with the first step and is the default.
Things to avoid :
• Duplicate name for EXEC statements invoking procedure. If RESTART=procsexec.stepname is used, the first procexec found will be used.
• Duplicate stepnames within procedure. If RESTART=procsexec.stepname is used, the first stepname within procexec found will be used.
• Duplicate stepnames. If RESTART=stepname is used, the first stepname found will be used.
• EXEC statements (invoking procedures or any step) without names. No restart is possible
• Creating and passing temporary datasets. Such datasets are always deleted by the time the job terminates and, therfore unavailable for restarting.
• Creating and passing nontemporary datasets. If such a dataset is not received and assigned a permanent disposition, Job Termination will delete it, making restart impossible
The TYPRUN parameter
This parameter requests special processing for the job.
General Syntax
TYPRUN={HOLD|JCLHOLD|SCAN|COPY} keyword parameter
HOLD - Job will held (and not executed temporarily) until the operator uses a command to release. A job will be held in the input queue only if syntactically correct
JCLHOLD (JES2 only) – Job will held (and not executed) until the operator uses a command to release it. Note the job will be held in queue if it is syntactically incorrect. Rarely used
SCAN – Job will be scanned for all syntactical JCL errors but will not execute.
COPY (JES2 only)- Job will be printed. No execution and no syntax checking takes place. Rarely used.
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3. The EXEC Statement
An EXEC statement identifies a step during the reading the reading process when a job is submitted to the system. When an EXEC is found, the system accepts all JCL statements that follow as belonging to the step, until a delimiter is found. There are four possible delimiters for a step during the reading process :
• Another EXEC statement in the input stream. It signals the end of (reading) one step and the beginning of (reading) of another.
• A JOB statement
• A null statement i.e //. All JCL statements will be ignored except for a JOB statement.
• End-of-file on the reading device, meaning there are no more statements to read.
General Syntax
//[stepname] EXEC parameters
stepname is optional. When the stepname is omitted no reference can be made. A job can contain a maximum of 255 steps.
The PGM Parameter
The PGM parameter identifies the program to be executed in a step.
General Syntax
PGM=pgmname positional parameter
Pgmname - Name of the program to be fetched from the loadlibrary and executed.
The program specified in PGM is always a member of library (PDS). This is commonly known as an executable program library or a load library. The EXEC statement can identify only the member. It has no parameter available to identify the library. If necessary, this must be done by using a JOBLIB or a STEPLIB DD statement.
E.g.3.1
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//joblib dd dsn=da0001t.lib.loadlib=shr
//s1 exec pgm=ass1
OR
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//s1 exec pgm=ass1
//steplib dd dsn=da0001t.lib.loadlib=shr
If neither JOBLIB or STEPLIB is coded, the system searches certain predefined libraries. They are the system default libraries. If the specified member is found, it is executed. If not found, the result is S806-04 ABEND failure.
The following keyword parameters can be specified at the EXEC statement. They are REGION, ADDRSPC, TIME , PARM and ACCT.
The REGION Parameter
This parameter specifies the limit of available storage for the step within the job’s address space.
General Syntax
REGION=value{K|M} keyword parameter
Value – 1 to 2096128 if K (1024 bytes) is used. It should be an even number, it will be rounded to the next higher even number.
Value – 1 to 2047 if M (1024K or 1048576 bytes) is used. M is not available to MVS/SP, only to MVS/XA and MVS/ESA
If the REGION parameter is omitted , the REGION parameter in the EXEC statements within the job will be used. If it is coded in neither the JOB nor the EXEC statement, an installation-defined default will be used. The default value of most installations is between 500K and 1000K.
If the REGION parameter is coded in both the JOB and an EXEC statement within the job, the value in the JOB statement will be used.
The REGION parameter in the JOB statement is used much more often than the one in the EXEC statement. Coding the same value for all steps would have the same effect as the REGION parameter in the JOB statement.
E.g. 3.2
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//s1 exec pgm=ass1,region=500k
//steplib dd dsn=da0001t.lib.loadlib=shr
The TIME parameter
This parameter specifies the total amount of CPU time that the step is allowed to use.
General Syntax
TIME=([minutes][,seconds] | [1440]) keyword parameter
minutes - a number from 1 to 1439
seconds – a number from 1 to 59
1440 - The step will not be timed for CPU. It was also not “time out” (S522 ABEND failure) when a single wait state exceeds the installation-defined limit (often 10 to 20 minutes). Note that TIME=1440 is rarely used, and most installation disallow its use in a testing environment. TIME=1440 should be used by an on-line system like CICS OR ADS/O.
When the TIME parameter is omitted, an installation-defined default will be used. This default is usually very high and unlikely to cause an S322 ABEND failure.
If the TIME parameter is also coded in the JOB statement, both will be in effect and either can cause a S322 ABEND failure. It is not advisable to use them both.
Remark :
It is possible for a step to get more CPU time than that is specified in the TIME parameter or the default by a maximum 10.5 seconds. This is due to the fact that the system checks for violations every 10.5 seconds.
E.g 3.3
//da0001ta job la2719,pcs,msglevel=(1,0),notify=&sysuid
//s1 exec pgm=ass1,region=500k,time=(,3)
//steplib dd dsn=da0001t.lib.loadlib=shr
The ADDRSPC parameter
This parameter specifies if the step will use real or virtual storage.
General syntax
ADDRSPC={VIRT|REAL}
VIRT – The REGION will be virtual storage and is the default
REAL – The REGION will be real storage.
If the ADDRSPC parameter is also coded in the JOB statement, the value in the JOB will be used.
Remark:
This is the rarely used parameter because of the default. Note that ADDRSPC=REAL is a parameter that is disallowed in practically all installation because it can cause serious performance problems for other jobs.
The ACCT Parameter
The parameter specifies accounting information to be used for the step as opposed to the accounting information in the JOB statement.
General Syntax
ACCT=(acctno [additional-acct-info]) keyword parameter
Acctno – The account number to be used for the step
Additional-acct-info – same as in the JOB statement.
The ACCT parameter is seldom used, and when it is, only the account number normally appears. This is used to charge resource utilization for a step to a different account number other than the one coded in the JOB statement.
If an account number is also coded in the JOB statement, the account number in the EXEC statement will be used.
E.g 3.4
//da0001ta job la2719,pcs,msglevel=(1,0),notify=&sysuid
//s1 exec pgm=iefbr14,acct=(‘es0013,hr4200,iefbr14’)
//dd1 dd dsn=da0001t.pai.empfile,disp=(mod,delete),
// space=(trk,0),unit=sysda
The PARM Parameter
This parameter provides a way to supply data of limited size to the executing program
General Syntax
PARM=string keyword parameter
String –A string of characters up to 100. If commas are part of the string, the entire field must be enclosed in parenthesis (or apostrophes). If any portion of the string contains special characters (other than hyphen), that portion of the entire string must be enclosed in apostrophes. Note that any parenthesis used count toward the maximum. Apostrophes do not.
All information after the “=” in the PARM parameter, excluding apostrophes, will be saved by the system within the step’s own region. When the program begins execution by using the appropriate instructions, it can find the saved information in storage.
In COBOL, the following must be coded :
LINKAGE SECTION.
01 PARM.
05 PLENGTH PIC S9(04) COMP.
05 INFO PIC X(05).
PROCEDURE DIVISION USING PARM.
0000-MAIN-PARA.
Note that any valid name may be used in place of PARM. The string is stored in PARM and the PLENGTH is set to the length of the string.
E.g 3.5
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//s1 exec pgm=ass2,parm=’g2 ‘,time=(,3)
//steplib dd dsn=da0001t.lib.loadlib=shr
Rules for continuation
E.g 3.6
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//cob exec pgm=ikfcbl00,region=1024k,
// parm=(‘notrunc,nodynam,lib,size=4096k,buf=116k’,
// ‘apost,nores,seq’)
.
.
or
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//cob exec pgm=ikfcbl00,region=1024k,
// parm=(notrunc,nodynam,lib,’size=4096k’,’buf=116k’,
// apost,nores,seq)
.
.
Note that an expression in quotes cannot be continued, we need to enclose the string in parenthesis and field containing special characters in apostrophes.
E.g.2 PARM=’29/06/00’ or (‘29/06/00’)
E.g 3 PARM=(A,B,C,D) or ‘A,B,C,D’
The two, however , are not the same. When parentheses are used, the information found by the program is (A,B,C,D). If apostrophes are used, the information found by the program is A,B,C,D.
The COND Parameter
The COND parameter can be coded in the JOB as well as the EXEC statement. It is mostly used in the EXEC statement. The main tool for controlling the execution of steps within a job is the COND parameter.
A Return (or Condition) code
A return code is a number between 0 and 4095, issued by an executing program just before its execution is finished. It is intended to identify an important event found (or not found) during the execution. For example, a program may issue a return code of 21 to indicate that a problematic event (such as a record is out of sequence) was detected during the execution or a return code of 0 to indicate that the execution was trouble free. The return code issued by a program is saved by the system for the duration of the job. Any subsequent step of the same job can interrogate this return code by using the COND parameter either in the JOB or EXEC statement. The result of this interrogation is to permit or bypass the execution of the step. Note that the return code is never available to a job other than the one issued it. In other words, the step that interrogates the return code must be in the same job as, and subsequent to, the step that issued it.
IBM-established conventions.
• Return code of 0 indicates a complete success.
• Return code of 4 indicates a warning. The warning is benign, so a return code will normally be treated as acceptable.
• Return code of 8 indicates a questionable results.
• Return code of 12 indicates bad results.
• Return code of 16 indicates a terminal condition.
The COND Parameter in the JOB statement.
The COND Parameter can perform a test (or multiple tests) at the beginning of each step against the return (condition) codes issued by the previous steps. If a test is satisfied , none of the steps from that point on will be executed.
General Syntax
COND=((code,operator) [,(code,operator)]…….) keyword parameter
Code - is a number between 0 and 4095
Operator – provides a comparison between a return code and the code. There are six operators : LT, LE, NE, EQ, GT, GE
There can be a maximum of eight tests in the COND parameter. Condition is evaluated from left to right and if a test is satisfied, the job stops execution at that point.
An example can best illustrate the mechanism of the COND parameter. Consider a job with five steps. Assume that none will ABEND.
//da0001ta job la2719,pcs,cond=((12,lt),(8,eq))
STEP1 issues a return code of 0
STEP2, if executed, issues a return code of 4
STEP3, if executed, issues a return code of 16
STEP4, if executed, issues a return code of 0
STEP5, if executed, issues a return code of 4
(warning : This example does not adhere to conventions.)
STEP 1 is executed by default, since no previous return codes exist and hence, the COND parameter in the JOB statement will be ignored for the first step.
Before STEP2 begins execution, the system interrogates the existing return code (0), using the tests in the COND parameter and reading the test from left to right,
• Is 12 less than 0? The answer is “no”. The first test of the COND parameter was not satisfied. The second test is tested.
• Is 8 equal to 0? . The answer is “no”. Neither of the two tests was satisfied, and therefore, STEP2 is executed.
Before STEP3 begins execution, the system interrogates the existing return codes (0 and 4), using the tests in the same COND parameter. Since the result for return code 0 is already known, only 4 will be tested :
• Is 12 less than 4? The answer is “no”. The first test of the COND parameter was not satisfied. The second test is tested.
• Is 8 equal to 4 . The answer is “no”. Neither of the two tests was satisfied, and therefore, STEP3 is executed.
Before STEP4 begins execution, the system interrogates the existing return codes (0 , 4 and 16), using the tests in the same COND parameter. Since the results for return code 0 and 4 are already known, only 16 will be tested :
• Is 12 less than 16? The answer is “yes”. The first test of the COND parameter was satisfied. There is no need for the second test . Executions of the job stops. STEP 4 and the remaining steps will not be executed.
A message will appear in the output:
IEF2011 DA0001TA STEP4-JOB TERMINATED BECAUSE OF CONDITION CODES.
A formula can be devised and used to code the COND parameter, if return code conventions are strictly adhered to :
COND=(last-good-return-code,LT)
Or
COND=(first-bad-return-code,LE)
Let us apply this formula to this example 0-4 is a good return code :
4 -is the last good return code….COND=(4,LT)
or
5 - is the first bad return code…..COND=(5,LE)
The two COND parameters are logically equivalent to each other, and it makes no difference which one is used.
Exercise : Code the COND parameter, where 0 is the only good return code.
The COND parameter in the EXEC statement
The COND parameter can perform a test (or multiple tests) before a step begins execution against the return (condition) codes issued by previous steps. If a test is satisfied, the step will not be executed.
General Syntax
COND=((code,operator[,stepname])[,(code,operator[,stepname])]……[,EVEN|ONLY]) keyword parameter
Code - is a number between 0 and 4095
Operator – provides a comparison between a return code and the code. There are six operators : LT, LE, NE, EQ, GT, GE
Stepname – Identifies the name of the preceding step whose return code will be interrogated. It can also appear as two names procexec.stepname where “procexec” identifies the name of the EXEC statement invoking a procedure and “stepname” the stepname within the procedure.
EVEN - requests that execution be permitted even though a previous (any previous) step has ABENDed.
ONLY - requests that execution be permitted only if a previous (any previous) step has ABENDed.
There can be a maximum of eight tests in the COND parameter. EVEN or ONLY counts toward eight. Condition is evaluated from left to right and if a test is satisfied, only that step is not executed.
Remark :
• EVEN and ONLY cannot make reference to a particular step. They refer to any previous step that has ABENDed.
• EVEN and ONLY are mutually exclusive
• EVEN and ONLY have no positional significance. Each can be coded anywhere in the COND parameter in relation to other tests
• Following an ABEND failure, a step cannot be executed unless it contains EVEN or ONLY in the COND parameter of its EXEC statement
• The first step will always be executed unless COND=ONLY appears in the exec statement. COND=ONLY would cause the first step to be bypassed, since no previous ABEND failures could have occurred. Any other COND parameter in the first EXEC statement will be ignored (i.e., COND=(4,LT) or COND=EVEN) or will result in JCL error (i.e., COND=(5,LT,stepname)) – since there are no previous step.
• A step that is not executed issues no return code because a program responsible for for issuing the return code was not even loaded into the storage. As a result no return code exists. An attempt to interrogate the return code of such a step in the COND parameter of a subsequent step will be ignored.
• A step that ABEND’s issues no return code because a program always issues a return code (conditionally or by default) if it reaches the end of its execution and intentionally returns control to the system. When an ABEND occurs, the program loses control instantly. And is evicted from from execution by the system. As a result when a step ABEND’s no return code exists ( a completion code exists). An attempt to interogate the return code of such a step in the COND parameter of a step will be ignored until it contains EVEN or ONLY.
An example can best illustrate the mechanism of the COND parameter. Consider a job with five steps. This is a class room exercise.
//da0001ta job la2719,pcs,notify=&sysuid,msglevel=(1,1)
//s1 exec pgm=p1 (4)
//s2 exec pgm=p2,cond=((0,lt,s1),even) (12)
//s3 exec pgm=p3,cond=(8,lt,s2) (0)
//s4 exec pgm=p4,cond=(4,lt) (8)
//s5 exec pgm=p5,cond=((4,lt,s1),(0,lt,s3)) abend
//s6 exec pgm=p6,cond=(even,(0,le,s5),) (16)*
//s7 exec pgm=p7,cond=((0,lt,s1),even) (0)
//s8 exec pgm=p8,cond=((0,lt,s1),(12,lt,s3) ) (0)
//s9 exec pgm=p9,cond=only) (4)
//s10 exec pgm=p10,cond=only (0)
If the COND parameter is coded neither at the JOB nor at the EXEC statement, the step will be executed regardless of previous return codes. However it will not be if a previous step has ABENDed.
If the COND parameter is coded in both the JOB statement as well as an EXEC statement within the JOB. The COND parameter of the JOB statement is tested first. If none of its tests are satisfied, then the COND parameter of the EXEC statement is tested. If a test is satisfied, none of the steps from that point on will be executed.
This is a class room exercise.
//DA0001TA JOB LA2719,PCS,COND=(5,EQ),NOTIFY=DA0001T
//S1 EXEC PGM=P1 (4)
//S2 EXEC PGM=P2,COND=(7,LT) (ABEND)
//S3 EXEC PGM=P3,COND=((20,GT,S1),EVEN) (6)
//S4 EXEC PGM=P4,COND=(3,EQ),ONLY) (8)
//S5 EXEC PGM=P5,COND=(2,LT,S3) -
//S6 EXEC PGM=P6 -
//S7 EXEC PGM=P7,COND=((6,EQ,S5),ONLY) (5)
//S8 EXEC PGM=P8,COND=EVEN (0)
//S9 EXEC PGM=P9 -
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• Another EXEC statement in the input stream. It signals the end of (reading) one step and the beginning of (reading) of another.
• A JOB statement
• A null statement i.e //. All JCL statements will be ignored except for a JOB statement.
• End-of-file on the reading device, meaning there are no more statements to read.
General Syntax
//[stepname] EXEC parameters
stepname is optional. When the stepname is omitted no reference can be made. A job can contain a maximum of 255 steps.
The PGM Parameter
The PGM parameter identifies the program to be executed in a step.
General Syntax
PGM=pgmname positional parameter
Pgmname - Name of the program to be fetched from the loadlibrary and executed.
The program specified in PGM is always a member of library (PDS). This is commonly known as an executable program library or a load library. The EXEC statement can identify only the member. It has no parameter available to identify the library. If necessary, this must be done by using a JOBLIB or a STEPLIB DD statement.
E.g.3.1
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//joblib dd dsn=da0001t.lib.loadlib=shr
//s1 exec pgm=ass1
OR
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//s1 exec pgm=ass1
//steplib dd dsn=da0001t.lib.loadlib=shr
If neither JOBLIB or STEPLIB is coded, the system searches certain predefined libraries. They are the system default libraries. If the specified member is found, it is executed. If not found, the result is S806-04 ABEND failure.
The following keyword parameters can be specified at the EXEC statement. They are REGION, ADDRSPC, TIME , PARM and ACCT.
The REGION Parameter
This parameter specifies the limit of available storage for the step within the job’s address space.
General Syntax
REGION=value{K|M} keyword parameter
Value – 1 to 2096128 if K (1024 bytes) is used. It should be an even number, it will be rounded to the next higher even number.
Value – 1 to 2047 if M (1024K or 1048576 bytes) is used. M is not available to MVS/SP, only to MVS/XA and MVS/ESA
If the REGION parameter is omitted , the REGION parameter in the EXEC statements within the job will be used. If it is coded in neither the JOB nor the EXEC statement, an installation-defined default will be used. The default value of most installations is between 500K and 1000K.
If the REGION parameter is coded in both the JOB and an EXEC statement within the job, the value in the JOB statement will be used.
The REGION parameter in the JOB statement is used much more often than the one in the EXEC statement. Coding the same value for all steps would have the same effect as the REGION parameter in the JOB statement.
E.g. 3.2
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//s1 exec pgm=ass1,region=500k
//steplib dd dsn=da0001t.lib.loadlib=shr
The TIME parameter
This parameter specifies the total amount of CPU time that the step is allowed to use.
General Syntax
TIME=([minutes][,seconds] | [1440]) keyword parameter
minutes - a number from 1 to 1439
seconds – a number from 1 to 59
1440 - The step will not be timed for CPU. It was also not “time out” (S522 ABEND failure) when a single wait state exceeds the installation-defined limit (often 10 to 20 minutes). Note that TIME=1440 is rarely used, and most installation disallow its use in a testing environment. TIME=1440 should be used by an on-line system like CICS OR ADS/O.
When the TIME parameter is omitted, an installation-defined default will be used. This default is usually very high and unlikely to cause an S322 ABEND failure.
If the TIME parameter is also coded in the JOB statement, both will be in effect and either can cause a S322 ABEND failure. It is not advisable to use them both.
Remark :
It is possible for a step to get more CPU time than that is specified in the TIME parameter or the default by a maximum 10.5 seconds. This is due to the fact that the system checks for violations every 10.5 seconds.
E.g 3.3
//da0001ta job la2719,pcs,msglevel=(1,0),notify=&sysuid
//s1 exec pgm=ass1,region=500k,time=(,3)
//steplib dd dsn=da0001t.lib.loadlib=shr
The ADDRSPC parameter
This parameter specifies if the step will use real or virtual storage.
General syntax
ADDRSPC={VIRT|REAL}
VIRT – The REGION will be virtual storage and is the default
REAL – The REGION will be real storage.
If the ADDRSPC parameter is also coded in the JOB statement, the value in the JOB will be used.
Remark:
This is the rarely used parameter because of the default. Note that ADDRSPC=REAL is a parameter that is disallowed in practically all installation because it can cause serious performance problems for other jobs.
The ACCT Parameter
The parameter specifies accounting information to be used for the step as opposed to the accounting information in the JOB statement.
General Syntax
ACCT=(acctno [additional-acct-info]) keyword parameter
Acctno – The account number to be used for the step
Additional-acct-info – same as in the JOB statement.
The ACCT parameter is seldom used, and when it is, only the account number normally appears. This is used to charge resource utilization for a step to a different account number other than the one coded in the JOB statement.
If an account number is also coded in the JOB statement, the account number in the EXEC statement will be used.
E.g 3.4
//da0001ta job la2719,pcs,msglevel=(1,0),notify=&sysuid
//s1 exec pgm=iefbr14,acct=(‘es0013,hr4200,iefbr14’)
//dd1 dd dsn=da0001t.pai.empfile,disp=(mod,delete),
// space=(trk,0),unit=sysda
The PARM Parameter
This parameter provides a way to supply data of limited size to the executing program
General Syntax
PARM=string keyword parameter
String –A string of characters up to 100. If commas are part of the string, the entire field must be enclosed in parenthesis (or apostrophes). If any portion of the string contains special characters (other than hyphen), that portion of the entire string must be enclosed in apostrophes. Note that any parenthesis used count toward the maximum. Apostrophes do not.
All information after the “=” in the PARM parameter, excluding apostrophes, will be saved by the system within the step’s own region. When the program begins execution by using the appropriate instructions, it can find the saved information in storage.
In COBOL, the following must be coded :
LINKAGE SECTION.
01 PARM.
05 PLENGTH PIC S9(04) COMP.
05 INFO PIC X(05).
PROCEDURE DIVISION USING PARM.
0000-MAIN-PARA.
Note that any valid name may be used in place of PARM. The string is stored in PARM and the PLENGTH is set to the length of the string.
E.g 3.5
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//s1 exec pgm=ass2,parm=’g2 ‘,time=(,3)
//steplib dd dsn=da0001t.lib.loadlib=shr
Rules for continuation
E.g 3.6
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//cob exec pgm=ikfcbl00,region=1024k,
// parm=(‘notrunc,nodynam,lib,size=4096k,buf=116k’,
// ‘apost,nores,seq’)
.
.
or
//da0001ta job la2719,pcs,msglevel=(1,1),notify=&sysuid
//cob exec pgm=ikfcbl00,region=1024k,
// parm=(notrunc,nodynam,lib,’size=4096k’,’buf=116k’,
// apost,nores,seq)
.
.
Note that an expression in quotes cannot be continued, we need to enclose the string in parenthesis and field containing special characters in apostrophes.
E.g.2 PARM=’29/06/00’ or (‘29/06/00’)
E.g 3 PARM=(A,B,C,D) or ‘A,B,C,D’
The two, however , are not the same. When parentheses are used, the information found by the program is (A,B,C,D). If apostrophes are used, the information found by the program is A,B,C,D.
The COND Parameter
The COND parameter can be coded in the JOB as well as the EXEC statement. It is mostly used in the EXEC statement. The main tool for controlling the execution of steps within a job is the COND parameter.
A Return (or Condition) code
A return code is a number between 0 and 4095, issued by an executing program just before its execution is finished. It is intended to identify an important event found (or not found) during the execution. For example, a program may issue a return code of 21 to indicate that a problematic event (such as a record is out of sequence) was detected during the execution or a return code of 0 to indicate that the execution was trouble free. The return code issued by a program is saved by the system for the duration of the job. Any subsequent step of the same job can interrogate this return code by using the COND parameter either in the JOB or EXEC statement. The result of this interrogation is to permit or bypass the execution of the step. Note that the return code is never available to a job other than the one issued it. In other words, the step that interrogates the return code must be in the same job as, and subsequent to, the step that issued it.
IBM-established conventions.
• Return code of 0 indicates a complete success.
• Return code of 4 indicates a warning. The warning is benign, so a return code will normally be treated as acceptable.
• Return code of 8 indicates a questionable results.
• Return code of 12 indicates bad results.
• Return code of 16 indicates a terminal condition.
The COND Parameter in the JOB statement.
The COND Parameter can perform a test (or multiple tests) at the beginning of each step against the return (condition) codes issued by the previous steps. If a test is satisfied , none of the steps from that point on will be executed.
General Syntax
COND=((code,operator) [,(code,operator)]…….) keyword parameter
Code - is a number between 0 and 4095
Operator – provides a comparison between a return code and the code. There are six operators : LT, LE, NE, EQ, GT, GE
There can be a maximum of eight tests in the COND parameter. Condition is evaluated from left to right and if a test is satisfied, the job stops execution at that point.
An example can best illustrate the mechanism of the COND parameter. Consider a job with five steps. Assume that none will ABEND.
//da0001ta job la2719,pcs,cond=((12,lt),(8,eq))
STEP1 issues a return code of 0
STEP2, if executed, issues a return code of 4
STEP3, if executed, issues a return code of 16
STEP4, if executed, issues a return code of 0
STEP5, if executed, issues a return code of 4
(warning : This example does not adhere to conventions.)
STEP 1 is executed by default, since no previous return codes exist and hence, the COND parameter in the JOB statement will be ignored for the first step.
Before STEP2 begins execution, the system interrogates the existing return code (0), using the tests in the COND parameter and reading the test from left to right,
• Is 12 less than 0? The answer is “no”. The first test of the COND parameter was not satisfied. The second test is tested.
• Is 8 equal to 0? . The answer is “no”. Neither of the two tests was satisfied, and therefore, STEP2 is executed.
Before STEP3 begins execution, the system interrogates the existing return codes (0 and 4), using the tests in the same COND parameter. Since the result for return code 0 is already known, only 4 will be tested :
• Is 12 less than 4? The answer is “no”. The first test of the COND parameter was not satisfied. The second test is tested.
• Is 8 equal to 4 . The answer is “no”. Neither of the two tests was satisfied, and therefore, STEP3 is executed.
Before STEP4 begins execution, the system interrogates the existing return codes (0 , 4 and 16), using the tests in the same COND parameter. Since the results for return code 0 and 4 are already known, only 16 will be tested :
• Is 12 less than 16? The answer is “yes”. The first test of the COND parameter was satisfied. There is no need for the second test . Executions of the job stops. STEP 4 and the remaining steps will not be executed.
A message will appear in the output:
IEF2011 DA0001TA STEP4-JOB TERMINATED BECAUSE OF CONDITION CODES.
A formula can be devised and used to code the COND parameter, if return code conventions are strictly adhered to :
COND=(last-good-return-code,LT)
Or
COND=(first-bad-return-code,LE)
Let us apply this formula to this example 0-4 is a good return code :
4 -is the last good return code….COND=(4,LT)
or
5 - is the first bad return code…..COND=(5,LE)
The two COND parameters are logically equivalent to each other, and it makes no difference which one is used.
Exercise : Code the COND parameter, where 0 is the only good return code.
The COND parameter in the EXEC statement
The COND parameter can perform a test (or multiple tests) before a step begins execution against the return (condition) codes issued by previous steps. If a test is satisfied, the step will not be executed.
General Syntax
COND=((code,operator[,stepname])[,(code,operator[,stepname])]……[,EVEN|ONLY]) keyword parameter
Code - is a number between 0 and 4095
Operator – provides a comparison between a return code and the code. There are six operators : LT, LE, NE, EQ, GT, GE
Stepname – Identifies the name of the preceding step whose return code will be interrogated. It can also appear as two names procexec.stepname where “procexec” identifies the name of the EXEC statement invoking a procedure and “stepname” the stepname within the procedure.
EVEN - requests that execution be permitted even though a previous (any previous) step has ABENDed.
ONLY - requests that execution be permitted only if a previous (any previous) step has ABENDed.
There can be a maximum of eight tests in the COND parameter. EVEN or ONLY counts toward eight. Condition is evaluated from left to right and if a test is satisfied, only that step is not executed.
Remark :
• EVEN and ONLY cannot make reference to a particular step. They refer to any previous step that has ABENDed.
• EVEN and ONLY are mutually exclusive
• EVEN and ONLY have no positional significance. Each can be coded anywhere in the COND parameter in relation to other tests
• Following an ABEND failure, a step cannot be executed unless it contains EVEN or ONLY in the COND parameter of its EXEC statement
• The first step will always be executed unless COND=ONLY appears in the exec statement. COND=ONLY would cause the first step to be bypassed, since no previous ABEND failures could have occurred. Any other COND parameter in the first EXEC statement will be ignored (i.e., COND=(4,LT) or COND=EVEN) or will result in JCL error (i.e., COND=(5,LT,stepname)) – since there are no previous step.
• A step that is not executed issues no return code because a program responsible for for issuing the return code was not even loaded into the storage. As a result no return code exists. An attempt to interrogate the return code of such a step in the COND parameter of a subsequent step will be ignored.
• A step that ABEND’s issues no return code because a program always issues a return code (conditionally or by default) if it reaches the end of its execution and intentionally returns control to the system. When an ABEND occurs, the program loses control instantly. And is evicted from from execution by the system. As a result when a step ABEND’s no return code exists ( a completion code exists). An attempt to interogate the return code of such a step in the COND parameter of a step will be ignored until it contains EVEN or ONLY.
An example can best illustrate the mechanism of the COND parameter. Consider a job with five steps. This is a class room exercise.
//da0001ta job la2719,pcs,notify=&sysuid,msglevel=(1,1)
//s1 exec pgm=p1 (4)
//s2 exec pgm=p2,cond=((0,lt,s1),even) (12)
//s3 exec pgm=p3,cond=(8,lt,s2) (0)
//s4 exec pgm=p4,cond=(4,lt) (8)
//s5 exec pgm=p5,cond=((4,lt,s1),(0,lt,s3)) abend
//s6 exec pgm=p6,cond=(even,(0,le,s5),) (16)*
//s7 exec pgm=p7,cond=((0,lt,s1),even) (0)
//s8 exec pgm=p8,cond=((0,lt,s1),(12,lt,s3) ) (0)
//s9 exec pgm=p9,cond=only) (4)
//s10 exec pgm=p10,cond=only (0)
If the COND parameter is coded neither at the JOB nor at the EXEC statement, the step will be executed regardless of previous return codes. However it will not be if a previous step has ABENDed.
If the COND parameter is coded in both the JOB statement as well as an EXEC statement within the JOB. The COND parameter of the JOB statement is tested first. If none of its tests are satisfied, then the COND parameter of the EXEC statement is tested. If a test is satisfied, none of the steps from that point on will be executed.
This is a class room exercise.
//DA0001TA JOB LA2719,PCS,COND=(5,EQ),NOTIFY=DA0001T
//S1 EXEC PGM=P1 (4)
//S2 EXEC PGM=P2,COND=(7,LT) (ABEND)
//S3 EXEC PGM=P3,COND=((20,GT,S1),EVEN) (6)
//S4 EXEC PGM=P4,COND=(3,EQ),ONLY) (8)
//S5 EXEC PGM=P5,COND=(2,LT,S3) -
//S6 EXEC PGM=P6 -
//S7 EXEC PGM=P7,COND=((6,EQ,S5),ONLY) (5)
//S8 EXEC PGM=P8,COND=EVEN (0)
//S9 EXEC PGM=P9 -
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4. The DD statement
A DD (Data Definition_ statement must appear in a step when the executing program expects to read from or write to a dataset. In other words DD statement describes the dataset. The DD statement is the most complicated of all the JCL statements.
The maximum number of DD statements in a step is 3273 . The DD statement can be coded in any order and always appear after the EXEC statement with the exeception of
JOBLIB, JOBCAT, PROCLIB DD statement.
The DSN Parameter
The DSN (or DSNAME) parameter identifies the name of the dataset to be created or retreived.
General Syntax
DSN=name| referback keyword parameter
Name - It could be a qualified name. This name consists of two or more simple name separated by periods for a maximum of 44 characters.
E.g 1 DSN=da0001t.pcs.empfile
E.g.2 DSN=da0001t.pcs.cobol(ass1) identifies a library (da0001t.pcs.cobol) and a particular member. This notation describes a sequential dataset.
e.g.3 DSN=&&name
A simple name preceded by two ampersands identifies a temporary dataset. Temporary because it is not retained beyond job termination.
The system generates a name with the following format :
SYSyyddd.Thh.mm.ss.RV001.jobname.name
Yyddd – Julian Calender;
hhmmss – uses 24 hour clock ;
RV001 –system provided information in reference to the reader;
jobname – as it appears in the JOB statement ;
Name – whatever is coded after &&.
For e.g DSN=&&temp
SYS00173.T090000.RV001.da0001ta.temp
Remark :
If the DSN name is omitted from a DD statement (except DD * , SYSOUT and DUMMY) also indicates a temporary dataset. However the system generates a name with the following format :
SYSyyddd.Thhmmss.RV001.jobname.R0000001
//SORTWK1 DD UNIT=SYSDA,SPACE=(TRK,(1,2),RLSE)
SYS00173.T100000.RV001.da0001ta.R0000001
This form is basically used when a step requires a work dataset (a dataset created at the beginning of the step’s exeution and deleted at the end). Mostly by utilities.
Most utility uses this form
Referback : This can have three formats :
- *.stepname.ddname – Requests that the dataset name be copied from DD statement “ddname “ found in a previous step “stepname”.
e.g : DSN=*.step1.dd1
- *.ddname – Requests that the dataset name be copied from a previous DD statement “ddname “ found in the same step “stepname”.
e.g : DSN=*.dd1
- *.procexec.stepname.ddname – Requests that the dataset name be copied from DD statement “ddname “ found in a previous step “stepname” found within procedure “procexec”. (name of EXEC statement invokinh the procedure)
e.g : DSN=*.ps1.step1.dd1
The DISP Parameter
The DISP parameter specifies :
- if the dataset is to be created or retreived
- how to dispose of the dataset when the step terminates (normally or abnormally)
General Syntax
NEW ,DELETE ,DELETE
OLD ,KEEP ,KEEP
DISP= ( SHR ,CATLG ,CATLG ) keyword parameter
MOD ,UNCATLG ,UNCATG;
,PASS
DISP=(status-field,normal-disp-field,abnormal-disp-field)
The status-field : This field tells the system whether the dataset is to be created or retrieved.
NEW – Indicates that the dataset will be created in this step
OLD - Indicates that an existing dataset will be retrieved and demands exclusive control.
SHR - Indicates that an existing dataset will be retrieved. It also indicates that this dataset ,if on disk, can be shared with one or more other users.
MOD - This subparameter has two possible meanings :
Indicates that an existing dataset will be retrieved . This will be true if
• The dataset is either cataloged or passed
• The DD statement contains either VOL=SER or VOL=REF (a VOL VOL=REF referring to a DD statement, which is a nonspecific request for a new dataset, is not included)
Indicates that the dataset will be created. This is true if :
• The DD statement contains neither VOL=SER nor VOL=REF and it describes a dataset which is neither cataloged nor passed.
• The DD statement contains VOL=REF referring to a DD statement which is nonspecific request for a new dataset.
e.g. 1 //dd1 dd dsn=da0001t.empfile,disp=(mod,catlg),
// unit=tape
Explanation:
1. The system assumes da0001t.empfile to be an existing dataset, since the DD statement contains neither VOL=SER or VOL=REF. The system searches the catalog and gets volume informatiom from the catalog entry. The volume have been found. This dataset will be treted as existing dataset.
2. Had the dataset been neither cataloged nor passed. The systen would have been unable to find the volume information and MOD will default to new.
e.g 2 //dd1 dd dsn=da0001t.empfile,disp=(mod,catlg),
// unit=sysda,vol=ser=bs3003,space=(trk,(1,2))
Explanation: Since VOL=SER is specified, the fate of MOD is sealed, whether or not it exists. It will be treated as OLD (with appropriate positioning). If the dataset exists on that volume no problem, however, if it does not exist the result will be S213-04 ABEND failure (i.e dataset does not exists)
Note :When UNIT and VOL=SER is specified the system does not search the catalog to locate the dataset.
The normal disposition field : This field is used to tell the system how to dispose of the dataset when the step terminates normally (without an ABEND).
DELETE – indicates that the dataset is to be deleted when the step terminates. For an existing dataset, OLD, SHR or MOD (not defaulting to NEW), the dataset will also be uncataloged, if the catalog were used while retreiving the dataset. It will only delete if the catalog were not used during the retrieval. This means that for a cataloged dataset, if you specify UNIT and VOL=SER the system does not search the catalog.
Note :
1 When a tape dataset is deleted, nothing happens. A tape dataset cannot be deleted through the DISP parameter. It is effectively deleted when the dataset is written over.
2 A VSAM cluster cannot be deleted by coding DISP=(OLD,DELETE) as it defaults to DISP=(OLD,KEEP).
3 A member of PDS cannot be deleted, as DISP applies to the entire PDS, and as result it deletes the entire PDS. Use either TSO or IEHPROGM utility.
4 The system always issues a message indicating “ DELETED’ or “NOT DELETED N” N indicates the reason for failing.
KEEP – Indicates that the dataset is to be kept when the step terminates. The system takes no action and issues a message indicating the dataset was kept. Again, the system issues a message “KEPT”. Note that “NOT KEPT” message does not exists.
Note : KEEP does not imply CATLG. As a result, DISP=(NEW,KEEP) should be rarely used because next time you retrieve the dataset, you need to specify UNIT and VOL=SER.
CATLG – Indicates that the dataset is to be kept and an entry for it placed in the catalog when the step terminates.
Note :
1. If cataloging is successful, the system issues “CATALOGED”
2. If cataloging fails for a NEW dataset, the message will “NOT CATLGD n”
(n indicates the reason for failing).
3. If the dataset to be catologed is OLD or MOD , which was opened but did extend into additional volume(s), the message will “RECATALOGED n”
4. If the dataset to be cataloged is OLD or MOD and has extended into additional volume(s), the message will be “recataloged”
5. CATLG implies KEEP. DISP=(NEW,CATLG,DELETE) is a very common parameter.
When an attempt to catalog fails ?
Explanation: Under certain conditions, the attempt to catalog a new entry fails. The step termination routines normally issue a message to inform the user :
IEF287I dataset name
IEF287I VOL=SER=BS3001, BS3003 NOT CATLGD n
Followed by the message identifing the user catalog where the attempt to add the entry was made.
IEF285I user catalog name
IEF285I VOL=SER=vol serial KEPT
“n” identifies the reason for which the cataloging operation failed.
Often, n is 2. There are several reasons for failing to catalog a dataset. Most of them are seldom encountered. For instance, the failure could be due to an I/O error or an out-of-space condition in the catalog, both extremely rare. The one that is common is illustrated by means of an example.
//dd1 dd dsn=da0001t.empfile,disp=(new,catlg,delete),
// space=(trk,(1,2)),unit=sysda,
// dcb=(lrecl=80,recfm=fb,blksize=800)
If an entry for DA0001T.EMPFILE already exists in the catalog, the step termination routines will not replace the existing entry with the new one, however it keeps the dataset and issues the appropriate message. Unfortunately, “NOT CATLGD 2 “ is just a warning, operator tend to ignore.
Whenever, you get this message. The existing entry must be removed before the one with the same one is added. Use IEHPROGM or any other utility to remove the catalog before adding a new one.
What are the implications of ignoring this warning ? Assume that the existing catalog entry for dataset points to BS3001, which may or may not contain such a dataset. As a result of DD statement DD1 the dataset by the same name has been created and kept on different volume say BS3008 while the catalog entry remains unaltered.
Later, the user, who did not notice the “NOT CATLGD 2” message submits a job containing a DD statement.
//infile dd dsn=da0001t.emfile,disp=shr
The system will search the catalog, retrieves the dataset residing on volume BS3001, with no outward appearance of failure. If the dataset by that name does not exist, the result is S213-04 ABEND failure.
Note that an attempt to add a dulpicate entry in the volume encounters a “DULPCIPATE NAME ON DIRECT ACCESS VOLUME” JCL error.
This problem is not encountered in MVS/ESA, because the system deletes the dataset as well as uncatalog.
PASS – Indicates that an entry for the dataset (containing dsn, volume and unit information) be placed on a table in storage (Passed Dataset Queue). This entry is to be used in a subsequent step to “receive the passed dataset”. A message will appear “PASSED”.
The abnormal (or conditional) disposition field : This field is used to tell the systen how to dispose of the dataset when the step terminates abnormally (ABENDs). It is required only if this disposition is different from the normal disposition.
DELETE,KEEP,CATLG, and UNCATLG have the same meaning they do in the normal disposition. Note that PASS is not permitted in the abnormal disposition field.
The best example of using the abnormal disposition field is DISP=(NEW,CATLG,DELETE). If there is ABEND, the dataset is to be deleted. This eliminates future manual intervention to delete and uncatalog the dataset in order to restart.
Defaults: Some defaults in the DISP parameter are fixed and others variable.
• If the DISP parameter is omitted, the default is always (NEW,DELETE.
//sysut1 dd unit=sysda,space=(trk,(1,2))
//* (NEW,DELETE) IS THE DEFAULT
• If the status is omitted, the default is always NEW
DISP=(,CATLG) is same as DISP=(NEW,CATLG)
• If the normal disposition field is omitted
- If the status field is NEW, the default is DELETE
- If the status field is OLD or SHR and the dataset name non temporary
If the DD statement is not receiving a passed dataset, the default is KEEP.
//dd1 dd dsn=da0001t.empfile,disp=shr
• If a DD statement is receiving a passed dataset, which was created during the execution of the job and was never given a permanent disposition, the default is DELETE.
• If a DD statement is receiving a passed dataset, which was created during the execution of the job but was given permanent disposition since being created, the default is KEEP.
• If a DD statement is receiving a passed dataset which existed before the job began execution, the default is KEEP.
• If the status field is OLD or SHR and the dataset name temporary, the default is pass.
//dd1 dd dsn=old,dsn=&&temp
DISP=OLD defaults to DISP=(OLD,PASS) and the message will appear in the output –“INVALID DISP FIELD – PASS SUBSTITUTED”
• If the abnormal disposition field is omitted, the default is the normal disposition field.
The UNIT Parameter
The UNIT parameter identifies :
The device type or device address where the volume is mounted. The volume is the one where the dataset resides (or will reside if DISP=NEW).
• The number of devices to be allocated to the dataset.
• When the mount message is to be shown to the operator.
General Syntax
device address
UNIT =( generic device name ,device count ,DEFER ) Keyword parameter
generated device name
device address – Identifies the exact device address. This notation is almost never used.
Generic device name – Identifies the device type using a universal system-supplied name.
e.g : UNIT=3390 ; UNIT=3400-5 ; UNIT=3480
generated device name – Identifies the device type using an installation-defined name.
UNIT=SYSDA ; UNIT=DISK ; UNIT=TAPE
The generated names can be made to mean whatever an installation wishes them to mean. For example, UNIT=SYSDA can mean all 3380 devices of any density, or single density only, or a subset of double density devices or a combination of 3380 and 3390 device. Their definition can vary from installation to installation. Our GE machine has UNIT=SYSALLDA.
Of the three, the generated name is far the most commonly used.
Device count – Specifies the number of devices to be allocated for the dataset. The limit is 59 devices. If omitted default is 1 except when DD statement describes a disk multivolume dataset. In such case, device count=number of volumes.
E.g. 1 UNIT=(SYSDA,5) ; UNIT=(TAPE,2)
E.g. 2 UNIT=SYSDA is same as UNIT=(SYSDA,1) because of default
E.g. 3 //dd1 dd dsn=da0001t.empfile,disp=(,catlg,delete),
// unit=sysda,vol=ser=(bs3001,bs3002,bs3003),
// space=(trk,(1,2)),dcb=(lrecl=80,recfm=fb,
// blksize=800)
In this example UNIT =SYSDA defaults to UNIT=(SYSDA,3)
Note : UNIT=(,2) can also be used if the device is being supplied by the catalog.
DEFER : Requests that the mount message to the operator not be issued by the allocation routines but by the open routines when, and, if the dataset is opened.
Note : DEFER must never be used with disk. Generally, used for tapes.
There is no default for device name. If it is not coded in the UNIT parameter and it is also not supplied by the catalog, the Passed dataset Queue, the result will be allocation JCL error . The message is
“IEF210I JOBNAME STEPNAME DDANAME –UNIT FIELD SPECIFIES INCORRECT DEVICE NAME”, which is misleading. It means that the device name was needed but not coded.
The VOL Parameter
The main function of the VOL (or VOLUME) is to identify the volume(s) by serial number where an existing dataset resides or where a new dataset will reside.
General Syntax
vol ,SER=(vol1 [,vol2]…….
Volume =( ,REF=referback
,REF=dsname
SER=(vol1,vol2….) – Specifies the serial number(s) of the volume(s) to be used. The maximum number of volumes is 255.
A volume serial is a combination of alphabetic , numeric, and national characters ($ @ #) up to 6. A hyphen is also permitted. In a real (or production) environment, the number of characters is almost never less than 6.
e.g VOL=SER=BS3001 OR VOLUME=SER=BS3001
VOL=SER=(BS3013,BS3014)
REF=referback
Referback – This can have three formats :
*.stepname.ddname - Requests that the volume be the same as for DD statement “ddname” found in the previous step “stepname”.
VOL=REF=*.STEP2.DD1
*.ddname - Requests that the volume be the same as for previous DD statement “ddname” found in the same step “stepname”.
VOL=REF=*.DD1
*.procexec.stepname.ddname - Requests that the volume be the same as for DD statement “ddname” found in the previous step “stepname” found within a procecure “procexec” (name of EXEC statement invoking the procedure.
VOL=REF=*.PR1.STEP2.DD1
Remark:
Referbacks are not encouraged. They should be used only when they are necessary. A referback with a “stepname” will cause a JCL error if the referenced step does not execute. Such referbacks must be avoided where restart is required.
REF=dsname – Requests that the volume be the same as the one where dataset “dsname” resides on. The dataset must be cataloged or Passed. The dataset does not even have to exist, as long as it is cataloged or passed. The name of the referenced dataset need not appear anywhere else in the job.
e.g : VOL=REF=DA0001T.EMPFILE
Remark:
When VOL=REF (referback or dsname) is used, the system supplies the volume as well as the unit information. Therefore, the UNIT parameter is usually unnecessary.
The SPACE Parameter
The SPACE parameter must be included in a DD statement when :
• A new disk dataset is created.
• An old dataset needs to alter its entitlement to additional space. i.e., Request additional disk space for an old dataset when available space is exausted.
• An old disk dataset must free up all unused space.
General Syntax
TRK,
SPACE=( CYL, (prim-alloc [,sec-alloc] [,directory]) [,RLSE])
Blksize,
TRK – Requests that space be allocated in tracks.
CYL – Requests that space be allocated in cylinders.
Blksize – Specifies the average blocksize of the dataset. The system will translate it to tracks.
Prim-alloc. Primary allocation or primary quantity. It identifies the number of tracks (if TRK is coded) or cylinders (if CYL is coded) or the number of blocks (if blksize is coded) that must be allocated during the allocation process for a new dataset before the step begins execution. The system will allocate the requested space in one extent. If this is not possible (and CONTIG is not coded), two extents will be used, then three and so on up to five extents. If as many as five extents still cannot satisy the request, the result will be a allocation JCL error :
IEF257I jobname stepname ddname –SPACE REQUESTED NOT AVAILABLE.
If the request is nonspecific (no VOL=SER or VOL=REF), needing a storage volume, the JCL error message will be different :
IEF257I jobname stepname ddname –INSUFFICIENT SPACE ON STORAGE VOLUMES.
Remark :
The system will always allocate the primary quantity in the least number of extents possible on a single volume. The primary quantity cannot be split over multiple volumes. The primary allocation cannot be omitted (coding 0 is allowed). It is ignored if the dataset is old.
e.g 1 SPACE=(TRK,3)
e.g 2 SPACE=(CYL,4)
e.g 3 SPACE=(23440,100)
e.g 5 SPACE=(TRK,0)
sec-alloc - Secondary allocation or secondary quantity. It identifies the number of tracks (if TRK is coded) or cylinders (if CYL is coded) or the number of blocks (if blksize is coded) that are to be allocated when all available space is exhausted while writing to a dataset. The system will allocate the secondary quantity in the least number of extents possible, and just like the primary quantity, it can be given in as many as five extents, if necessary.
The system will always supply the specified secondary allocation when one is needed unless one of the two events occurs :
• The allocated volume does not have enough space to satisfy the secondary allocation and no other volumes are allocated.
• The needed secondary allocation, if granted, will cause the dataset to exceed 16 extents on the volumes and no other volumes are allocated.
If either of these two conditions arises, the result will be a SB37-04 ABEND failure (normally for a sequential dataset). For a PDS, the ABEND, can also be SE37-04. Please note that a PDS is confined to a single volume, ehile a sequential dataset can extend into a maximum of 59 volumes. The 16-extent-per-volume limit for a dataset is system-supplied and cannot be altered.
The secondary allocation is optional. If omitted, defaults to 0. When no secondary allocation is coded and the primary allocation is exhausted, the result is an SD37-04 ABEND failure.
Remark :
The secondary allocation can be used for new as well as old datasets. The secondary allocation requested when the dataset is created is recorded in the dataset’s DSCB (VTOC entry). If space is exhausted when the dataset is retrieved as OLD and extended, the system attempts to provide secondary allocation appearing in the DSCB. If ,however, a SPACE parameter is included in the DD statement, the secondary allocation will be based on what is coded in this SPACE parameter rather than what appears in the dataset’s DSCB.
E.g 1 SPACE=(TRK,(1,2))
E.g 2 SPACE=(CYL,(7,4))
E.g 3 SPACE=(23440,(200,100))
directory – Specifies the number of directory blocks (256 bytes each) to be assigned to the directory of a PDS.
The directory quantity, if not coded, defaults to zero; therefore, the directory quantity must be specified for a new PDS. If it is, not S013-14 ABEND failure will occur if an attempt is made to add the first member to a PDS.
Remark :
The directory quantity is taken away from the beginning of the primary allocation if TRK or CYL is coded in the SPACE parameter. When blksize is coded, the system adds the directory blocks to the data blocks and then computes the amount of primary space.
E.g 1 SPACE=(TRK,(20,5,5)) OR SPACE=(TRK,(20,,5)) if no secondary
E.g 2 SPACE=(CYL,(20,5,5)) OR SPACE=(CYL,(20,,5)) if no secondary
E.g 3 SPACE=(23440,(200,50,5)) OR SPACE=(23440,(200,,5)) if no secondary
RLSE –Requests that any unused space be freed when the dataset is closed. This works for both new and old datasets, provided they were opened for output. Space will be released on the boundary used in the SPACE parameter. If tracks (or cylinders) were allocated, unused tracks (or cylinders), will be released.
Remark :
Using RLSE is highly recommended for datasets not intended for future expansions. Temporary datasets are ideal candidates. For datasets that expand in future runs, RLSE can result in a larger number of extents, and, possibly, a premature SB37-04 ABEND failure. RLSE will be ignored if the dataset is opened by another user (or shared by another job) ot the step ABEND’s.
e.g: SPACE=(TRK,(5,1),RLSE)
The LABEL Parameter
The LABEL parameter can specify :
• The sequence of a tape dataset on a volume.
• The type of label of the dataset.
General Syntax
LABEL=([seq-no][,type]) keyword parameter
Seq-no – Identifies the sequence number of the dataset on a tape volume. 1 to 4 digits. If omitted, it defaults to 1. If 0 is coded, it defaults to 1. Maximum : 9999
e.g LABEL=3
type – Identifies the type of label for the dataset.
There are many types of labels. To name a few, which are important from project perspective.
SL – Indicates IBM standard label. If the subparameter is omitted, SL is the default.
NL – Indicates no labels are used. NL is not commonly used. Normally, NL is used for a tape coming from or going to another installation which has no SL capabilities.
BLP – Bypass Label Processing : Indicates that labels will not be recognized and will be treated as ordinary files. BLP is used as a last resort when neither SL nor NL can accomplish what is required.
Label Verification : When retrieving an SL tape dataset, both the volume serial and the dataset name will be verified. When creating an SL tape dataset with VOL=SER or VOL=REF, only the volume serial will be verified.
When retrieving an NL tape dataset, neither the volume serial nor dataset name can be verified. However, only an NL tape volume can be mounted. An SL volume will be rejected.
Defaults : If omitted, the LABEL parameter defaults to (1,SL). There are four ways to supply the same information.
• Omit the LABEL parameter
• Code LABEL=(,SL) 1 is the default
• Code LABEL=1 SL is the default
SL
VOL HDR1 HDR2 TM SL DATA SET # 1 TM EOF1 EOF2 TM TM
NL
NL DATASET #1 TM NL DATASET #2 TM TM
TM – Tape Mark
The DCB Parameter
The DCB parameter specifies values to be used to complete the Data Control Block (DCB) when a dataset is opened. A DCB is constructed by the language processor (compiler or assembler), based on the appropriate instructions of the language being used, and resides inside the code of the program. The compiler, collects this information and defaults from various parts of the program (For e.g In COBOL, RECORD CONTAINS 80 CHARACTERS; BLOCK CONTAINS 10 RECORDS and so on ) and constructs the DCB. Note that the DCB exists only for non VSAM datasets and is checked by the OPEN routines (for input or output). Certain values must be “hard-coded” in the DCB by the program. Others can can be left out, giving the user the option of supplying these values via the DCB parameter( as well as other means).
There are three suppliers of DCB information :
• Values supplied by the program, referred to as hard-coded. When a value is hard-coded, it cannot be changed unless the program is changed.
• Values coded in the DCB parameter of the DD statement. These values will be ignored if they are already hard-coded.
• Values from the standard label of the dataset. The values supplied by the label are limited to : BLKSIZE,LRECL, RECFM, DSORG etc. Values from the label will not be used if they are hard-coded inside the program or coded in the DCB parameter.
General Syntax
DCB=([referback] | [model][,subparameter],…… keyword parameter
Referback – This can have three formats :
*.stepname.ddname - Requests that the DCB parameter be copied from the DD statement “ddname” found in the previous step “stepname”.
DCB=*.STEP2.DD1
*.ddname - Requests that the DCB parameter be copied from a previous DD statement “ddname” found in the same step “stepname”.
DCB=*.DD1
*.procexec.stepname.ddname - Requests that the DCB parameter be copied from DD statement “ddname” found in the previous step “stepname” found within a procecure “procexec” (name of EXEC statement invoking the procedure.
DCB=*.PR1.STEP2.DD1
Remark :
The DCB referback copies the DCB parameter as opposed to the DSN and VOL=REF referbacks which acquire the dataset name and the volser respectively, whether or not the DSN and VOL parameters are present in the referenced DD statement. If the DCB referback refers to a DD statement which contains no DCB, nothing is copied and no message appears.
Model – specifies the name of the dataset which :
• Must be cataloged. If it is not, the result will be a JCL error : IEF2121 jobname stepname ddname –DATASET NOT FOUND
• Must be on disk (Tapes not allowed)
• Must reside on a volume that is accessible (online)
This dataset is called a model DSCB. The DCB information from the label of the model is extracted and can be used.
E.g 1. DCB=DA0001T.EMPFILE
E.g 2. In case you want to override some of the subparameters, the overriding subparameters must follow the DSCB model dataset name.
DCB=(DA0001T.EMPFILE,LRECL=100,BLKSIZE=800)
Models, are generally used, during the creations of GDG’s and dummying the PDS.
Subparameters : There is vast number of subparameters, the great majority of which are seldom or never used.
• BLKSIZE -Specifies the size of the block (also known as the physical record). For RECFM=FB, the blocksize must be multiple of the logical record length, and it identifies the exact size of the block. For RECFM=VB, the blocksize can be any value up to the limit but atleast 4 bytes larger than the logical record length. For RECFM=U, the blocksize can be any value up to the limit
Remark : There is no default for BLKSIZE. Coding BLKSIZE=0, the system will compute the optimum blocksize based on the device type.
E.g DCB=BLKSIZE=800
LRECL – Specifies the size of the logical record. The maximum size is 32,760, and it cannot be larger than blocksize, unless RECFM=VBS is used.
E.g. DCB=(LRECL=80,BLKSIZE=800)
RECFM –Specifies the record format. There are several values (or combinations of values) that can be coded.
• F - All blocks and all logical records are fixed in size.
• V - Blocks as well as logical records are of variable size. The first 4 bytes of each block (and logical record) describes its length.
• B – One or more logical records reside in each block. B cannot be coded alone. It is used in conjunction with F or V. For example FB or VB.
• U – Blocks are of variable size. There are no logical records. Mainly used with Load Library.
• S- For fixed-size records, it indicates that no short blocks are permitted anywhere but the end of the data. For variable-size records, it indicates that a logical record can span more than one block. S cannot be coded alone. It must follow F,V,FB or VB.
• A – Indicates that the first character of each record is an ANSI control character to be used for printer carriage control. A cannot be coded alone. It must follow F,V,FB,VB or U.
E.g DCB=(LRECL=80,RECFM=FB,BLKSIZE=800)
If RECFM is not supplied through any means, U is the default.
DEN – Identifies the density of the tape. DEN=3(or 4) indicates 1600 (or 6250 ) BPI density.
BUFNO – Identifies the number of buffers to be allocated in virtual storage by the OPEN routines, which will contain the blocks to be rean in or written out. If omitted, default is 5. The maximum is 255. Coding for BUFNO a number greater than 5 may require that the REGION parameter be increased.
EROPT – Specifies what action to take if an unrecoverable I/O error occurs while reading or writing a block.
• ABE – Cause an ABEND failure (S001-1).
• SKP – Skip the block containing the error.
• ACC – Accept the block containing the error
The default is ABE
DSORG – Identifies the organization of the dataset
• PS – Specifies physical sequential organization. Mostly QSAM and sometimes BSAM.
• PO - Specifies partitioned organization (or BPAM)
• DA- Specifies direct organization (or BDAM)
• IS – Specifies indexed sequential organization(or ISAM)
ABEND failures due to inconsistent DCB values :
• S013-20 ABEND when RECFM=FB is used but the BLKSIZE is not an exact multiple of LRECL. Note that SYSOUT is an exception.
• S013-34 ABEND when RECFM=FB is used and the LRECL is greater than the BLKSIZE.
• S013-34 ABEND when RECFM=VB is used and the LRECL is greater than the BLKSIZE-4.
Remark :
If values for BLKSIZE or LRECL are not supplied by any source (hard-coded or the DCB parameter or DSCB), the result will be an S013-34 ABEND failure.
• S001-04 ABEND when BLKSIZE in the DCB parameter is smaller than the actual blocksize and is a multiple of the LRECL in the DSCB of the dataset.
It is important to understand which of these often-used parameters are normally hard-coded and which are not :
• BLKSIZE - Seldom hard-coded. The BLKSIZE is unrelated to the logic of the program and hard-coding its value would cause unnecessary changes whenever the BLKSIZE is changed. In COBOL, BLOCK CONTAINS 0 RECORDS must be coded to avoid hard-coding the BLKSIZE. Omitting this clause will cause a default of 1 to be used. The result will be a hard-coded BLKSIZE is equal to LRECL. Many installation standards disallow hard-coding the BLKSIZE for sequential and partitioned datasets.
• LRECL – Frequently hard-coded. The logic of any ordinary program is dependent on the LRECL and, as a result, the LRECL cannot be changed without changing the logic of the program. Many high-level languages like COBOL always hard-code the LRECL.
• RECFM – Frequently hard-coded. The logic of any ordinary program is dependent on the RECFM and, as a result, the RECFM cannot be changed without changing the logic of the program. Many high-level languages like COBOL always hard-code the RECFM.
Instream Data
The input stream submitted to the system for execution consists of two possible parts :
• JCL mandatory part of the input stream
• Data mixed in with JCL in the input stream. This data is known as sysin data or input stream data. It is optional part of the input stream and always has a logical record length of 80. Any records encountered in the input stream which are not JCL statements will be treated as sysin data.
Sysin data must be preceded by a DD statement such as :
//name dd *
data
/*
Sysin data encountered by JES2 or JES3 following a DD * statement will be saved on the SPOOL volume for future use. This is known as input spooling The sysin is delimited (the spooling stops) by :
• A /* (delimiter) statement found.
• A valid JCL statement.
• An end-of-file condition on reading device.
The asterisk (*) is a positional parameter. The DD * is a special statement which is under complete JES2 or JES3 control.
SYSIN is a very common ddname used by many vendor-written programs to pass control information to the utility. E.g SORT,IEBGENER,IDCAMS utilities.
In user writtem programs, if you use COBOL ACCEPT statement. In your run JCL one of the DD statements will be SYSIN dd statement.
//sysin dd *
1234
/*
With the above type of DD statement, one complication arises if the sysin data must consist of JCL statement. Because any JCL statement delimits sysin data. To accomplish this, DD DATA instead of DD * must be used.
//sysut1 dd data
1234
abcd
//dd1 dd dsn=da0001t.empfile,disp=shr
/*
A /* must be used to delimit a DD DATA statement. A word of caution: Failure to supply a /* will cause serious problems. JCL statements following DD DATA will unintentionally become part of sysin data. However, If you want /* to be part of sysin data, code DLM parameter.
//sysut1 dd data,dlm=’)(‘
1234
abcd
//dd1 dd dsn=da0001t.empfile,disp=shr
/*
xyz
)(
The two characters that are coded in the DLM parameter (apostrophes must be used for special characters) will act as a delimiter and /* will be treated as data. Any two characters can be used. However, characters that are likely to appear in the first two positions of any record must be avoided to prevent premature delimiting sysin data.
DD parameter Function
* For reading data without // or /* in columns 1 and 2.
DATA For reading data with // but not /* in columns 1 and 2 containing JCL or statements.
DLM For reading data with either // or /* in columns 1 and 2.
* and DATA are positional parameters whereas DLM is a keyword parameter.
Remark :
If sysin data is not preceded by DD *, the system will generate a statement and place it in front of the sysin data .
E.g
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//steplib dd …
1234
//dd1 dd …
is equivalent to
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//steplib dd …
//sysin dd * (generated statement)
1234
//dd1 dd …
Note : A line with blanks is the most common offender. It is invisible to the user but it will be treated as data by the system This may or may not cause problem. Let us look at the following example.
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//steplib dd …
//sysin dd *
1234
//dd1 dd …
The system will interpret the above JCL in the following way :
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//sysin dd *
//steplib dd …
//sysin dd * (generated statement)
1234
//dd1 dd …
Conclusion : If there are two or more DD statements by the same name in the same step. This is not an error condition. When the program opens for SYSIN the first of the two be used. The other will be allocated and ignored.
Remark :
Generically, each DD statement must have a unique ddname except in special cases viz concatenation. In JES2, if a step contains identical ddnames, the system allocates devices and space and does disposition processing for both the DD statements. However, the systen directs all references to the first DD statement with that name in the step. In JES3, if a step contains identical ddnames, the job ABEND’S during allocation.
The SYSOUT Parameter
Print records generated by a program are not normally routed directly to a physical printer(theoretically it is possible, but in practice it is seldom done). Instead, they are written on the SPOOL pack and saved there for later viewing on a terminal or printing (or both). This is called output spooling, and is under the control of JES2 or JES3 which later can use one of their print routines to print the dataset. These print routines must schedule the datasets for printing, and msgclasses are used for this purpose. All print routines (called printers or writers) are associated with one or more classes (in all 36 classes) and each dataset to printed must also be assigned classes. The printer routines selects datasets for printing in a very similar way as initiators selects jobs for executions. Use S.ST option of ISPF menu to view the output dataset.
The SYSOUT parameter can assign this class, known as sysout or output class, to a dataset. Such datasets are called sysout or output datsets.
General Syntax
SYSOUT=(class| *) keyword parameter
Class – Identifies the sysout class of the dataset from A to Z and 0 to 9.
*- Indicates that the same class used in the MSGCLASS parameter of the JOB statement (or the installation-defined default, if MSGCLASS parameter is omitted) is to be used.
E.g 1. sysout=a
E.g 2 //sysprint dd sysout=*
This DD statement is used for printing system messages generated by JES2 or JES3. Each step must have SYSPRINT DD statement. Absence will cause “ SYSPRINT DD STATEMENT MISSING” message in the sysout.
E.g 3 //sysout dd sysout=* (or any sysout class may be assigned)
This DD statement is used when you have COBOL DISPLAY clause in your program.
Concatenation
Concatenating Datasets
At times, program may have to read in sequence several input datasets as if they were one. This can accomplished without physically putting the data in one datasets. This is done by concatenating the datasets in JCL code with comparable DCB characteristics without programming changes.
Note that only sequential and partitioned datasets can be concatenated. For sequential datasets, the maximum number of concatenations is 255 and for PDS it is 16. Concatenation has meaning only for sequential processing.
E.g 1. Concatenation of physical sequential files.
//dd1 dd dsn=da0001t.pcs.group1,disp=shr
// dd dsn=da0001t.pcs.group2,disp=shr
// dd dsn=da0001t.pcs.group3,disp=shr
E.g 2. Concatenation of partitioned datasets.
//dd1 dd dsn=da0001t.pds1.group1,disp=shr
// dd dsn=da0001t.pds2.group2,disp=shr
// dd dsn=da0001t.pds3.group3,disp=shr
There are number of rules and restrictions for concatenations :
1. The first concatenation is the only one with a ddname.
2. The logical record length and the record format of concatenated datasets must be the same. However, the blocksizes need not be.
3. The blocksize of the first concatenation must be greater than or equal to blocksizes of all subsequent concatenation. Violation of this rule results in S001-04 ABEND failure. This is true for DFP Version 2.3. For version DFP 2.4, one can concatenate datasets in any sequence, but for the first concatenation code the DCB parameter with the largest blocksize of all the concatenations.
E.g. Assume that in the JCL below, the first concatenation has a blocsize of 800, the second a blocksize of 800- and the third a blocksize of 23400.
//infile dd dsn=da0001t.pcs.group1,disp=shr,dcb=23400
// dd dsn=da0001t.pcs.group2,disp=shr
// dd dsn=da0001t.pcs.group3,disp=shr
4. Both sequential datasets and partitioned datasets can be concatenated, but not with each other – sequential with sequential and partitioned with partitioned only. Member of a PDS is treated as sequential dataset and thus can be concatenated with sequential dataset.
E.g
//in dd dsn=da0001t.empfile,disp=shr
// dd dsn=da0001t.pcs.data(emp),disp=shr
5. Disk as well as tape datasets can be concatenated but not with each other. Only like devices should be concatenated, disk with disk and tape with tape.
DUMMY Parameter
The DUMMY parameter is a positional parameter. At times, one might want to execute a program but suppress read or write operations in certain jobs, For example., not print a report. At other times, one might want to test a program without actually processing data.
The DUMMY parameter specifies that :
• No device or external storage be allocated.
• No disposition processing is performed.
• No input or output operations are performed for sequential access methods.
Remark :
1 DCB information is established. Generally used during testing process and in procedures. Instead of using DUMMY, one may use DSN=NULLFILE. It differs from DUMMY by virtue of its position. It is a keyword parameter.
E.g //DD1 DD DSN=NULLFILE
2 When an attempt to dummy a PDS is made will cause an S013-64 ABEND failure.
3 The DCB parameter may be required while coding DUMMY. Failure to do so may cause an S013-10 ABEND failure.
4 DUMMY provides a safe way to eliminate I/O activity when required.
The JOBLIB DD Statement
The JOBLIB statement identifies the program library (load library) where the programs to be executed throughout the job resides. It must be placed between the JOB and the first EXEC statement.
E.g :
//da0001ta job,la2719,……
//joblib dd dsn=da0001t.lib.loadlib,disp=shr
//s1 exec pgm=proga
//s2 exec pgm=progb
Expanation : PROGA (and PROGB) is expected to reside in DA0001T.LIB.LOADLIB as a member of a library and the system searches the directory. If not found will search certain predefined libraries and the S806-04 ABEND failure occurs.
Remark :
A JOBLIB DD statement can have several concatenations (max: 16)
E.g
//da0001ta job,la2719,……
//joblib dd dsn=da0001t.lib.loadlib,disp=shr
// dd dsn=da0001t.lib1.loadlib,disp=shr
// dd dsn=da0001t.prod.loadlib,disp=shr
//s1 exec pgm=proga
Explanation : All concatenations may be searched to locate a program. If, however, the program is found in a concatenation other than the last one, other concatenations will not be used. Note that, if a duplicate names exist in different concatenations, the user can decide which one is to be executed by determining the sequence of the concatenations.
The STEPLIB STATEMENT
The STEPLIB statement identifies the program library (load library) where the program to be executed for the step where STEPLIB resides. It can be placed anywhere after the EXEC statement.
E.g 1:
//da0001ta job,la2719,……
//s1 exec pgm=proga
//steplib dd dsn=da0001t.lib.loadlib,disp=shr
//s2 exec pgm=progb
//steplib dd dsn=da0001t.lib.loadlib1,disp=shr
Explanation : Program PROGA is expected to reside in DA0001TA.LIB.LOADLIB as a member of the library. If not found, will search certain predefined libraries and the S806-04 ABEND failure occurs.
E.g 2:
//da0001ta job,la2719,……
//joblib dd dsn=da0001t.lib.loadlib1,disp=shr
//s1 exec pgm=proga
//s2 exec pgm=progb
//steplib dd dsn=da0001t.lib.loadlib,disp=shr
//s3 exec pgm=progc
A STEPLIB DD statement has the effect of negating the JOBLIB DD statement for a particular step.
STORAGE DUMP
When a step encounters an ABEND failure, it is often advantageous to request a virtual storage dump, which can then be helpful in determining the cause of an ABEND. To request a storage dump, one of the following three DD statements must be included in the step :
• A SYSUDUMP DD statement
• A SYSMDUMP DD statement
• A SYSABEND DD statement
//sysudump dd sysout=*
All virtual storage allocated to your program i.e user region of job’s address space. It is a formatted dump. SYSUDUMP usually writes to sysout. It can, however, write to a disk dataset, providing a way to preserve the SYSUDUMP information for later viewing and analysis.
//sysudump dd dsn=da0001t.dumpfile,space=(trk,(0,5),rlse),
// disp=(,delete,catlg),unit=sysda
No DCB is required.
Remark :
SYSUDUMP DD statement is more often used.
//sysmudump dd sysout=*
This is same as SYSUDUMP DD statement except for the fact that the dump is nonformatted. This type of dump is very difficult to analyze unless it is saved on a disk and then processed by the PRDUMP service aid.
SYSMDUMP is seldom used.
//sysabend dd sysout=*
When a SYSUDUMP DD statement is included in a step which ABEND’s, a formatted virtual storage dump will be provided. This dump will also include information about the failed step, as well as most of the MVS storage-resident information which is of no use to the average user. SYSABEND is intended for system programmer.
Remark :
1 If neither a SYSUDUMP nor a SYSMDUMP nor a SYSABEND statement is coded wihin a JCL of an ABENDing step, a small amount of information is provided. This information is seldom useful in resolving the problem that caused the ABEND failure.
2 If more than one of the above statements is included in the JCL of a step, only the last one will be used. The previous ones will be ignored.
//s1 exec pgm=ass1
//sysabend dd sysout=*
//sysudump dd sysout=*
Note that SYSUDUMP will be in use.
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The maximum number of DD statements in a step is 3273 . The DD statement can be coded in any order and always appear after the EXEC statement with the exeception of
JOBLIB, JOBCAT, PROCLIB DD statement.
The DSN Parameter
The DSN (or DSNAME) parameter identifies the name of the dataset to be created or retreived.
General Syntax
DSN=name| referback keyword parameter
Name - It could be a qualified name. This name consists of two or more simple name separated by periods for a maximum of 44 characters.
E.g 1 DSN=da0001t.pcs.empfile
E.g.2 DSN=da0001t.pcs.cobol(ass1) identifies a library (da0001t.pcs.cobol) and a particular member. This notation describes a sequential dataset.
e.g.3 DSN=&&name
A simple name preceded by two ampersands identifies a temporary dataset. Temporary because it is not retained beyond job termination.
The system generates a name with the following format :
SYSyyddd.Thh.mm.ss.RV001.jobname.name
Yyddd – Julian Calender;
hhmmss – uses 24 hour clock ;
RV001 –system provided information in reference to the reader;
jobname – as it appears in the JOB statement ;
Name – whatever is coded after &&.
For e.g DSN=&&temp
SYS00173.T090000.RV001.da0001ta.temp
Remark :
If the DSN name is omitted from a DD statement (except DD * , SYSOUT and DUMMY) also indicates a temporary dataset. However the system generates a name with the following format :
SYSyyddd.Thhmmss.RV001.jobname.R0000001
//SORTWK1 DD UNIT=SYSDA,SPACE=(TRK,(1,2),RLSE)
SYS00173.T100000.RV001.da0001ta.R0000001
This form is basically used when a step requires a work dataset (a dataset created at the beginning of the step’s exeution and deleted at the end). Mostly by utilities.
Most utility uses this form
Referback : This can have three formats :
- *.stepname.ddname – Requests that the dataset name be copied from DD statement “ddname “ found in a previous step “stepname”.
e.g : DSN=*.step1.dd1
- *.ddname – Requests that the dataset name be copied from a previous DD statement “ddname “ found in the same step “stepname”.
e.g : DSN=*.dd1
- *.procexec.stepname.ddname – Requests that the dataset name be copied from DD statement “ddname “ found in a previous step “stepname” found within procedure “procexec”. (name of EXEC statement invokinh the procedure)
e.g : DSN=*.ps1.step1.dd1
The DISP Parameter
The DISP parameter specifies :
- if the dataset is to be created or retreived
- how to dispose of the dataset when the step terminates (normally or abnormally)
General Syntax
NEW ,DELETE ,DELETE
OLD ,KEEP ,KEEP
DISP= ( SHR ,CATLG ,CATLG ) keyword parameter
MOD ,UNCATLG ,UNCATG;
,PASS
DISP=(status-field,normal-disp-field,abnormal-disp-field)
The status-field : This field tells the system whether the dataset is to be created or retrieved.
NEW – Indicates that the dataset will be created in this step
OLD - Indicates that an existing dataset will be retrieved and demands exclusive control.
SHR - Indicates that an existing dataset will be retrieved. It also indicates that this dataset ,if on disk, can be shared with one or more other users.
MOD - This subparameter has two possible meanings :
Indicates that an existing dataset will be retrieved . This will be true if
• The dataset is either cataloged or passed
• The DD statement contains either VOL=SER or VOL=REF (a VOL VOL=REF referring to a DD statement, which is a nonspecific request for a new dataset, is not included)
Indicates that the dataset will be created. This is true if :
• The DD statement contains neither VOL=SER nor VOL=REF and it describes a dataset which is neither cataloged nor passed.
• The DD statement contains VOL=REF referring to a DD statement which is nonspecific request for a new dataset.
e.g. 1 //dd1 dd dsn=da0001t.empfile,disp=(mod,catlg),
// unit=tape
Explanation:
1. The system assumes da0001t.empfile to be an existing dataset, since the DD statement contains neither VOL=SER or VOL=REF. The system searches the catalog and gets volume informatiom from the catalog entry. The volume have been found. This dataset will be treted as existing dataset.
2. Had the dataset been neither cataloged nor passed. The systen would have been unable to find the volume information and MOD will default to new.
e.g 2 //dd1 dd dsn=da0001t.empfile,disp=(mod,catlg),
// unit=sysda,vol=ser=bs3003,space=(trk,(1,2))
Explanation: Since VOL=SER is specified, the fate of MOD is sealed, whether or not it exists. It will be treated as OLD (with appropriate positioning). If the dataset exists on that volume no problem, however, if it does not exist the result will be S213-04 ABEND failure (i.e dataset does not exists)
Note :When UNIT and VOL=SER is specified the system does not search the catalog to locate the dataset.
The normal disposition field : This field is used to tell the system how to dispose of the dataset when the step terminates normally (without an ABEND).
DELETE – indicates that the dataset is to be deleted when the step terminates. For an existing dataset, OLD, SHR or MOD (not defaulting to NEW), the dataset will also be uncataloged, if the catalog were used while retreiving the dataset. It will only delete if the catalog were not used during the retrieval. This means that for a cataloged dataset, if you specify UNIT and VOL=SER the system does not search the catalog.
Note :
1 When a tape dataset is deleted, nothing happens. A tape dataset cannot be deleted through the DISP parameter. It is effectively deleted when the dataset is written over.
2 A VSAM cluster cannot be deleted by coding DISP=(OLD,DELETE) as it defaults to DISP=(OLD,KEEP).
3 A member of PDS cannot be deleted, as DISP applies to the entire PDS, and as result it deletes the entire PDS. Use either TSO or IEHPROGM utility.
4 The system always issues a message indicating “ DELETED’ or “NOT DELETED N” N indicates the reason for failing.
KEEP – Indicates that the dataset is to be kept when the step terminates. The system takes no action and issues a message indicating the dataset was kept. Again, the system issues a message “KEPT”. Note that “NOT KEPT” message does not exists.
Note : KEEP does not imply CATLG. As a result, DISP=(NEW,KEEP) should be rarely used because next time you retrieve the dataset, you need to specify UNIT and VOL=SER.
CATLG – Indicates that the dataset is to be kept and an entry for it placed in the catalog when the step terminates.
Note :
1. If cataloging is successful, the system issues “CATALOGED”
2. If cataloging fails for a NEW dataset, the message will “NOT CATLGD n”
(n indicates the reason for failing).
3. If the dataset to be catologed is OLD or MOD , which was opened but did extend into additional volume(s), the message will “RECATALOGED n”
4. If the dataset to be cataloged is OLD or MOD and has extended into additional volume(s), the message will be “recataloged”
5. CATLG implies KEEP. DISP=(NEW,CATLG,DELETE) is a very common parameter.
When an attempt to catalog fails ?
Explanation: Under certain conditions, the attempt to catalog a new entry fails. The step termination routines normally issue a message to inform the user :
IEF287I dataset name
IEF287I VOL=SER=BS3001, BS3003 NOT CATLGD n
Followed by the message identifing the user catalog where the attempt to add the entry was made.
IEF285I user catalog name
IEF285I VOL=SER=vol serial KEPT
“n” identifies the reason for which the cataloging operation failed.
Often, n is 2. There are several reasons for failing to catalog a dataset. Most of them are seldom encountered. For instance, the failure could be due to an I/O error or an out-of-space condition in the catalog, both extremely rare. The one that is common is illustrated by means of an example.
//dd1 dd dsn=da0001t.empfile,disp=(new,catlg,delete),
// space=(trk,(1,2)),unit=sysda,
// dcb=(lrecl=80,recfm=fb,blksize=800)
If an entry for DA0001T.EMPFILE already exists in the catalog, the step termination routines will not replace the existing entry with the new one, however it keeps the dataset and issues the appropriate message. Unfortunately, “NOT CATLGD 2 “ is just a warning, operator tend to ignore.
Whenever, you get this message. The existing entry must be removed before the one with the same one is added. Use IEHPROGM or any other utility to remove the catalog before adding a new one.
What are the implications of ignoring this warning ? Assume that the existing catalog entry for dataset points to BS3001, which may or may not contain such a dataset. As a result of DD statement DD1 the dataset by the same name has been created and kept on different volume say BS3008 while the catalog entry remains unaltered.
Later, the user, who did not notice the “NOT CATLGD 2” message submits a job containing a DD statement.
//infile dd dsn=da0001t.emfile,disp=shr
The system will search the catalog, retrieves the dataset residing on volume BS3001, with no outward appearance of failure. If the dataset by that name does not exist, the result is S213-04 ABEND failure.
Note that an attempt to add a dulpicate entry in the volume encounters a “DULPCIPATE NAME ON DIRECT ACCESS VOLUME” JCL error.
This problem is not encountered in MVS/ESA, because the system deletes the dataset as well as uncatalog.
PASS – Indicates that an entry for the dataset (containing dsn, volume and unit information) be placed on a table in storage (Passed Dataset Queue). This entry is to be used in a subsequent step to “receive the passed dataset”. A message will appear “PASSED”.
The abnormal (or conditional) disposition field : This field is used to tell the systen how to dispose of the dataset when the step terminates abnormally (ABENDs). It is required only if this disposition is different from the normal disposition.
DELETE,KEEP,CATLG, and UNCATLG have the same meaning they do in the normal disposition. Note that PASS is not permitted in the abnormal disposition field.
The best example of using the abnormal disposition field is DISP=(NEW,CATLG,DELETE). If there is ABEND, the dataset is to be deleted. This eliminates future manual intervention to delete and uncatalog the dataset in order to restart.
Defaults: Some defaults in the DISP parameter are fixed and others variable.
• If the DISP parameter is omitted, the default is always (NEW,DELETE.
//sysut1 dd unit=sysda,space=(trk,(1,2))
//* (NEW,DELETE) IS THE DEFAULT
• If the status is omitted, the default is always NEW
DISP=(,CATLG) is same as DISP=(NEW,CATLG)
• If the normal disposition field is omitted
- If the status field is NEW, the default is DELETE
- If the status field is OLD or SHR and the dataset name non temporary
If the DD statement is not receiving a passed dataset, the default is KEEP.
//dd1 dd dsn=da0001t.empfile,disp=shr
• If a DD statement is receiving a passed dataset, which was created during the execution of the job and was never given a permanent disposition, the default is DELETE.
• If a DD statement is receiving a passed dataset, which was created during the execution of the job but was given permanent disposition since being created, the default is KEEP.
• If a DD statement is receiving a passed dataset which existed before the job began execution, the default is KEEP.
• If the status field is OLD or SHR and the dataset name temporary, the default is pass.
//dd1 dd dsn=old,dsn=&&temp
DISP=OLD defaults to DISP=(OLD,PASS) and the message will appear in the output –“INVALID DISP FIELD – PASS SUBSTITUTED”
• If the abnormal disposition field is omitted, the default is the normal disposition field.
The UNIT Parameter
The UNIT parameter identifies :
The device type or device address where the volume is mounted. The volume is the one where the dataset resides (or will reside if DISP=NEW).
• The number of devices to be allocated to the dataset.
• When the mount message is to be shown to the operator.
General Syntax
device address
UNIT =( generic device name ,device count ,DEFER ) Keyword parameter
generated device name
device address – Identifies the exact device address. This notation is almost never used.
Generic device name – Identifies the device type using a universal system-supplied name.
e.g : UNIT=3390 ; UNIT=3400-5 ; UNIT=3480
generated device name – Identifies the device type using an installation-defined name.
UNIT=SYSDA ; UNIT=DISK ; UNIT=TAPE
The generated names can be made to mean whatever an installation wishes them to mean. For example, UNIT=SYSDA can mean all 3380 devices of any density, or single density only, or a subset of double density devices or a combination of 3380 and 3390 device. Their definition can vary from installation to installation. Our GE machine has UNIT=SYSALLDA.
Of the three, the generated name is far the most commonly used.
Device count – Specifies the number of devices to be allocated for the dataset. The limit is 59 devices. If omitted default is 1 except when DD statement describes a disk multivolume dataset. In such case, device count=number of volumes.
E.g. 1 UNIT=(SYSDA,5) ; UNIT=(TAPE,2)
E.g. 2 UNIT=SYSDA is same as UNIT=(SYSDA,1) because of default
E.g. 3 //dd1 dd dsn=da0001t.empfile,disp=(,catlg,delete),
// unit=sysda,vol=ser=(bs3001,bs3002,bs3003),
// space=(trk,(1,2)),dcb=(lrecl=80,recfm=fb,
// blksize=800)
In this example UNIT =SYSDA defaults to UNIT=(SYSDA,3)
Note : UNIT=(,2) can also be used if the device is being supplied by the catalog.
DEFER : Requests that the mount message to the operator not be issued by the allocation routines but by the open routines when, and, if the dataset is opened.
Note : DEFER must never be used with disk. Generally, used for tapes.
There is no default for device name. If it is not coded in the UNIT parameter and it is also not supplied by the catalog, the Passed dataset Queue, the result will be allocation JCL error . The message is
“IEF210I JOBNAME STEPNAME DDANAME –UNIT FIELD SPECIFIES INCORRECT DEVICE NAME”, which is misleading. It means that the device name was needed but not coded.
The VOL Parameter
The main function of the VOL (or VOLUME) is to identify the volume(s) by serial number where an existing dataset resides or where a new dataset will reside.
General Syntax
vol ,SER=(vol1 [,vol2]…….
Volume =( ,REF=referback
,REF=dsname
SER=(vol1,vol2….) – Specifies the serial number(s) of the volume(s) to be used. The maximum number of volumes is 255.
A volume serial is a combination of alphabetic , numeric, and national characters ($ @ #) up to 6. A hyphen is also permitted. In a real (or production) environment, the number of characters is almost never less than 6.
e.g VOL=SER=BS3001 OR VOLUME=SER=BS3001
VOL=SER=(BS3013,BS3014)
REF=referback
Referback – This can have three formats :
*.stepname.ddname - Requests that the volume be the same as for DD statement “ddname” found in the previous step “stepname”.
VOL=REF=*.STEP2.DD1
*.ddname - Requests that the volume be the same as for previous DD statement “ddname” found in the same step “stepname”.
VOL=REF=*.DD1
*.procexec.stepname.ddname - Requests that the volume be the same as for DD statement “ddname” found in the previous step “stepname” found within a procecure “procexec” (name of EXEC statement invoking the procedure.
VOL=REF=*.PR1.STEP2.DD1
Remark:
Referbacks are not encouraged. They should be used only when they are necessary. A referback with a “stepname” will cause a JCL error if the referenced step does not execute. Such referbacks must be avoided where restart is required.
REF=dsname – Requests that the volume be the same as the one where dataset “dsname” resides on. The dataset must be cataloged or Passed. The dataset does not even have to exist, as long as it is cataloged or passed. The name of the referenced dataset need not appear anywhere else in the job.
e.g : VOL=REF=DA0001T.EMPFILE
Remark:
When VOL=REF (referback or dsname) is used, the system supplies the volume as well as the unit information. Therefore, the UNIT parameter is usually unnecessary.
The SPACE Parameter
The SPACE parameter must be included in a DD statement when :
• A new disk dataset is created.
• An old dataset needs to alter its entitlement to additional space. i.e., Request additional disk space for an old dataset when available space is exausted.
• An old disk dataset must free up all unused space.
General Syntax
TRK,
SPACE=( CYL, (prim-alloc [,sec-alloc] [,directory]) [,RLSE])
Blksize,
TRK – Requests that space be allocated in tracks.
CYL – Requests that space be allocated in cylinders.
Blksize – Specifies the average blocksize of the dataset. The system will translate it to tracks.
Prim-alloc. Primary allocation or primary quantity. It identifies the number of tracks (if TRK is coded) or cylinders (if CYL is coded) or the number of blocks (if blksize is coded) that must be allocated during the allocation process for a new dataset before the step begins execution. The system will allocate the requested space in one extent. If this is not possible (and CONTIG is not coded), two extents will be used, then three and so on up to five extents. If as many as five extents still cannot satisy the request, the result will be a allocation JCL error :
IEF257I jobname stepname ddname –SPACE REQUESTED NOT AVAILABLE.
If the request is nonspecific (no VOL=SER or VOL=REF), needing a storage volume, the JCL error message will be different :
IEF257I jobname stepname ddname –INSUFFICIENT SPACE ON STORAGE VOLUMES.
Remark :
The system will always allocate the primary quantity in the least number of extents possible on a single volume. The primary quantity cannot be split over multiple volumes. The primary allocation cannot be omitted (coding 0 is allowed). It is ignored if the dataset is old.
e.g 1 SPACE=(TRK,3)
e.g 2 SPACE=(CYL,4)
e.g 3 SPACE=(23440,100)
e.g 5 SPACE=(TRK,0)
sec-alloc - Secondary allocation or secondary quantity. It identifies the number of tracks (if TRK is coded) or cylinders (if CYL is coded) or the number of blocks (if blksize is coded) that are to be allocated when all available space is exhausted while writing to a dataset. The system will allocate the secondary quantity in the least number of extents possible, and just like the primary quantity, it can be given in as many as five extents, if necessary.
The system will always supply the specified secondary allocation when one is needed unless one of the two events occurs :
• The allocated volume does not have enough space to satisfy the secondary allocation and no other volumes are allocated.
• The needed secondary allocation, if granted, will cause the dataset to exceed 16 extents on the volumes and no other volumes are allocated.
If either of these two conditions arises, the result will be a SB37-04 ABEND failure (normally for a sequential dataset). For a PDS, the ABEND, can also be SE37-04. Please note that a PDS is confined to a single volume, ehile a sequential dataset can extend into a maximum of 59 volumes. The 16-extent-per-volume limit for a dataset is system-supplied and cannot be altered.
The secondary allocation is optional. If omitted, defaults to 0. When no secondary allocation is coded and the primary allocation is exhausted, the result is an SD37-04 ABEND failure.
Remark :
The secondary allocation can be used for new as well as old datasets. The secondary allocation requested when the dataset is created is recorded in the dataset’s DSCB (VTOC entry). If space is exhausted when the dataset is retrieved as OLD and extended, the system attempts to provide secondary allocation appearing in the DSCB. If ,however, a SPACE parameter is included in the DD statement, the secondary allocation will be based on what is coded in this SPACE parameter rather than what appears in the dataset’s DSCB.
E.g 1 SPACE=(TRK,(1,2))
E.g 2 SPACE=(CYL,(7,4))
E.g 3 SPACE=(23440,(200,100))
directory – Specifies the number of directory blocks (256 bytes each) to be assigned to the directory of a PDS.
The directory quantity, if not coded, defaults to zero; therefore, the directory quantity must be specified for a new PDS. If it is, not S013-14 ABEND failure will occur if an attempt is made to add the first member to a PDS.
Remark :
The directory quantity is taken away from the beginning of the primary allocation if TRK or CYL is coded in the SPACE parameter. When blksize is coded, the system adds the directory blocks to the data blocks and then computes the amount of primary space.
E.g 1 SPACE=(TRK,(20,5,5)) OR SPACE=(TRK,(20,,5)) if no secondary
E.g 2 SPACE=(CYL,(20,5,5)) OR SPACE=(CYL,(20,,5)) if no secondary
E.g 3 SPACE=(23440,(200,50,5)) OR SPACE=(23440,(200,,5)) if no secondary
RLSE –Requests that any unused space be freed when the dataset is closed. This works for both new and old datasets, provided they were opened for output. Space will be released on the boundary used in the SPACE parameter. If tracks (or cylinders) were allocated, unused tracks (or cylinders), will be released.
Remark :
Using RLSE is highly recommended for datasets not intended for future expansions. Temporary datasets are ideal candidates. For datasets that expand in future runs, RLSE can result in a larger number of extents, and, possibly, a premature SB37-04 ABEND failure. RLSE will be ignored if the dataset is opened by another user (or shared by another job) ot the step ABEND’s.
e.g: SPACE=(TRK,(5,1),RLSE)
The LABEL Parameter
The LABEL parameter can specify :
• The sequence of a tape dataset on a volume.
• The type of label of the dataset.
General Syntax
LABEL=([seq-no][,type]) keyword parameter
Seq-no – Identifies the sequence number of the dataset on a tape volume. 1 to 4 digits. If omitted, it defaults to 1. If 0 is coded, it defaults to 1. Maximum : 9999
e.g LABEL=3
type – Identifies the type of label for the dataset.
There are many types of labels. To name a few, which are important from project perspective.
SL – Indicates IBM standard label. If the subparameter is omitted, SL is the default.
NL – Indicates no labels are used. NL is not commonly used. Normally, NL is used for a tape coming from or going to another installation which has no SL capabilities.
BLP – Bypass Label Processing : Indicates that labels will not be recognized and will be treated as ordinary files. BLP is used as a last resort when neither SL nor NL can accomplish what is required.
Label Verification : When retrieving an SL tape dataset, both the volume serial and the dataset name will be verified. When creating an SL tape dataset with VOL=SER or VOL=REF, only the volume serial will be verified.
When retrieving an NL tape dataset, neither the volume serial nor dataset name can be verified. However, only an NL tape volume can be mounted. An SL volume will be rejected.
Defaults : If omitted, the LABEL parameter defaults to (1,SL). There are four ways to supply the same information.
• Omit the LABEL parameter
• Code LABEL=(,SL) 1 is the default
• Code LABEL=1 SL is the default
SL
VOL HDR1 HDR2 TM SL DATA SET # 1 TM EOF1 EOF2 TM TM
NL
NL DATASET #1 TM NL DATASET #2 TM TM
TM – Tape Mark
The DCB Parameter
The DCB parameter specifies values to be used to complete the Data Control Block (DCB) when a dataset is opened. A DCB is constructed by the language processor (compiler or assembler), based on the appropriate instructions of the language being used, and resides inside the code of the program. The compiler, collects this information and defaults from various parts of the program (For e.g In COBOL, RECORD CONTAINS 80 CHARACTERS; BLOCK CONTAINS 10 RECORDS and so on ) and constructs the DCB. Note that the DCB exists only for non VSAM datasets and is checked by the OPEN routines (for input or output). Certain values must be “hard-coded” in the DCB by the program. Others can can be left out, giving the user the option of supplying these values via the DCB parameter( as well as other means).
There are three suppliers of DCB information :
• Values supplied by the program, referred to as hard-coded. When a value is hard-coded, it cannot be changed unless the program is changed.
• Values coded in the DCB parameter of the DD statement. These values will be ignored if they are already hard-coded.
• Values from the standard label of the dataset. The values supplied by the label are limited to : BLKSIZE,LRECL, RECFM, DSORG etc. Values from the label will not be used if they are hard-coded inside the program or coded in the DCB parameter.
General Syntax
DCB=([referback] | [model][,subparameter],…… keyword parameter
Referback – This can have three formats :
*.stepname.ddname - Requests that the DCB parameter be copied from the DD statement “ddname” found in the previous step “stepname”.
DCB=*.STEP2.DD1
*.ddname - Requests that the DCB parameter be copied from a previous DD statement “ddname” found in the same step “stepname”.
DCB=*.DD1
*.procexec.stepname.ddname - Requests that the DCB parameter be copied from DD statement “ddname” found in the previous step “stepname” found within a procecure “procexec” (name of EXEC statement invoking the procedure.
DCB=*.PR1.STEP2.DD1
Remark :
The DCB referback copies the DCB parameter as opposed to the DSN and VOL=REF referbacks which acquire the dataset name and the volser respectively, whether or not the DSN and VOL parameters are present in the referenced DD statement. If the DCB referback refers to a DD statement which contains no DCB, nothing is copied and no message appears.
Model – specifies the name of the dataset which :
• Must be cataloged. If it is not, the result will be a JCL error : IEF2121 jobname stepname ddname –DATASET NOT FOUND
• Must be on disk (Tapes not allowed)
• Must reside on a volume that is accessible (online)
This dataset is called a model DSCB. The DCB information from the label of the model is extracted and can be used.
E.g 1. DCB=DA0001T.EMPFILE
E.g 2. In case you want to override some of the subparameters, the overriding subparameters must follow the DSCB model dataset name.
DCB=(DA0001T.EMPFILE,LRECL=100,BLKSIZE=800)
Models, are generally used, during the creations of GDG’s and dummying the PDS.
Subparameters : There is vast number of subparameters, the great majority of which are seldom or never used.
• BLKSIZE -Specifies the size of the block (also known as the physical record). For RECFM=FB, the blocksize must be multiple of the logical record length, and it identifies the exact size of the block. For RECFM=VB, the blocksize can be any value up to the limit but atleast 4 bytes larger than the logical record length. For RECFM=U, the blocksize can be any value up to the limit
Remark : There is no default for BLKSIZE. Coding BLKSIZE=0, the system will compute the optimum blocksize based on the device type.
E.g DCB=BLKSIZE=800
LRECL – Specifies the size of the logical record. The maximum size is 32,760, and it cannot be larger than blocksize, unless RECFM=VBS is used.
E.g. DCB=(LRECL=80,BLKSIZE=800)
RECFM –Specifies the record format. There are several values (or combinations of values) that can be coded.
• F - All blocks and all logical records are fixed in size.
• V - Blocks as well as logical records are of variable size. The first 4 bytes of each block (and logical record) describes its length.
• B – One or more logical records reside in each block. B cannot be coded alone. It is used in conjunction with F or V. For example FB or VB.
• U – Blocks are of variable size. There are no logical records. Mainly used with Load Library.
• S- For fixed-size records, it indicates that no short blocks are permitted anywhere but the end of the data. For variable-size records, it indicates that a logical record can span more than one block. S cannot be coded alone. It must follow F,V,FB or VB.
• A – Indicates that the first character of each record is an ANSI control character to be used for printer carriage control. A cannot be coded alone. It must follow F,V,FB,VB or U.
E.g DCB=(LRECL=80,RECFM=FB,BLKSIZE=800)
If RECFM is not supplied through any means, U is the default.
DEN – Identifies the density of the tape. DEN=3(or 4) indicates 1600 (or 6250 ) BPI density.
BUFNO – Identifies the number of buffers to be allocated in virtual storage by the OPEN routines, which will contain the blocks to be rean in or written out. If omitted, default is 5. The maximum is 255. Coding for BUFNO a number greater than 5 may require that the REGION parameter be increased.
EROPT – Specifies what action to take if an unrecoverable I/O error occurs while reading or writing a block.
• ABE – Cause an ABEND failure (S001-1).
• SKP – Skip the block containing the error.
• ACC – Accept the block containing the error
The default is ABE
DSORG – Identifies the organization of the dataset
• PS – Specifies physical sequential organization. Mostly QSAM and sometimes BSAM.
• PO - Specifies partitioned organization (or BPAM)
• DA- Specifies direct organization (or BDAM)
• IS – Specifies indexed sequential organization(or ISAM)
ABEND failures due to inconsistent DCB values :
• S013-20 ABEND when RECFM=FB is used but the BLKSIZE is not an exact multiple of LRECL. Note that SYSOUT is an exception.
• S013-34 ABEND when RECFM=FB is used and the LRECL is greater than the BLKSIZE.
• S013-34 ABEND when RECFM=VB is used and the LRECL is greater than the BLKSIZE-4.
Remark :
If values for BLKSIZE or LRECL are not supplied by any source (hard-coded or the DCB parameter or DSCB), the result will be an S013-34 ABEND failure.
• S001-04 ABEND when BLKSIZE in the DCB parameter is smaller than the actual blocksize and is a multiple of the LRECL in the DSCB of the dataset.
It is important to understand which of these often-used parameters are normally hard-coded and which are not :
• BLKSIZE - Seldom hard-coded. The BLKSIZE is unrelated to the logic of the program and hard-coding its value would cause unnecessary changes whenever the BLKSIZE is changed. In COBOL, BLOCK CONTAINS 0 RECORDS must be coded to avoid hard-coding the BLKSIZE. Omitting this clause will cause a default of 1 to be used. The result will be a hard-coded BLKSIZE is equal to LRECL. Many installation standards disallow hard-coding the BLKSIZE for sequential and partitioned datasets.
• LRECL – Frequently hard-coded. The logic of any ordinary program is dependent on the LRECL and, as a result, the LRECL cannot be changed without changing the logic of the program. Many high-level languages like COBOL always hard-code the LRECL.
• RECFM – Frequently hard-coded. The logic of any ordinary program is dependent on the RECFM and, as a result, the RECFM cannot be changed without changing the logic of the program. Many high-level languages like COBOL always hard-code the RECFM.
Instream Data
The input stream submitted to the system for execution consists of two possible parts :
• JCL mandatory part of the input stream
• Data mixed in with JCL in the input stream. This data is known as sysin data or input stream data. It is optional part of the input stream and always has a logical record length of 80. Any records encountered in the input stream which are not JCL statements will be treated as sysin data.
Sysin data must be preceded by a DD statement such as :
//name dd *
data
/*
Sysin data encountered by JES2 or JES3 following a DD * statement will be saved on the SPOOL volume for future use. This is known as input spooling The sysin is delimited (the spooling stops) by :
• A /* (delimiter) statement found.
• A valid JCL statement.
• An end-of-file condition on reading device.
The asterisk (*) is a positional parameter. The DD * is a special statement which is under complete JES2 or JES3 control.
SYSIN is a very common ddname used by many vendor-written programs to pass control information to the utility. E.g SORT,IEBGENER,IDCAMS utilities.
In user writtem programs, if you use COBOL ACCEPT statement. In your run JCL one of the DD statements will be SYSIN dd statement.
//sysin dd *
1234
/*
With the above type of DD statement, one complication arises if the sysin data must consist of JCL statement. Because any JCL statement delimits sysin data. To accomplish this, DD DATA instead of DD * must be used.
//sysut1 dd data
1234
abcd
//dd1 dd dsn=da0001t.empfile,disp=shr
/*
A /* must be used to delimit a DD DATA statement. A word of caution: Failure to supply a /* will cause serious problems. JCL statements following DD DATA will unintentionally become part of sysin data. However, If you want /* to be part of sysin data, code DLM parameter.
//sysut1 dd data,dlm=’)(‘
1234
abcd
//dd1 dd dsn=da0001t.empfile,disp=shr
/*
xyz
)(
The two characters that are coded in the DLM parameter (apostrophes must be used for special characters) will act as a delimiter and /* will be treated as data. Any two characters can be used. However, characters that are likely to appear in the first two positions of any record must be avoided to prevent premature delimiting sysin data.
DD parameter Function
* For reading data without // or /* in columns 1 and 2.
DATA For reading data with // but not /* in columns 1 and 2 containing JCL or statements.
DLM For reading data with either // or /* in columns 1 and 2.
* and DATA are positional parameters whereas DLM is a keyword parameter.
Remark :
If sysin data is not preceded by DD *, the system will generate a statement and place it in front of the sysin data .
E.g
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//steplib dd …
1234
//dd1 dd …
is equivalent to
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//steplib dd …
//sysin dd * (generated statement)
1234
//dd1 dd …
Note : A line with blanks is the most common offender. It is invisible to the user but it will be treated as data by the system This may or may not cause problem. Let us look at the following example.
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//steplib dd …
//sysin dd *
1234
//dd1 dd …
The system will interpret the above JCL in the following way :
//da0001ta job la2719,…..
//s1 exec pgm=ass1
//sysin dd *
//steplib dd …
//sysin dd * (generated statement)
1234
//dd1 dd …
Conclusion : If there are two or more DD statements by the same name in the same step. This is not an error condition. When the program opens for SYSIN the first of the two be used. The other will be allocated and ignored.
Remark :
Generically, each DD statement must have a unique ddname except in special cases viz concatenation. In JES2, if a step contains identical ddnames, the system allocates devices and space and does disposition processing for both the DD statements. However, the systen directs all references to the first DD statement with that name in the step. In JES3, if a step contains identical ddnames, the job ABEND’S during allocation.
The SYSOUT Parameter
Print records generated by a program are not normally routed directly to a physical printer(theoretically it is possible, but in practice it is seldom done). Instead, they are written on the SPOOL pack and saved there for later viewing on a terminal or printing (or both). This is called output spooling, and is under the control of JES2 or JES3 which later can use one of their print routines to print the dataset. These print routines must schedule the datasets for printing, and msgclasses are used for this purpose. All print routines (called printers or writers) are associated with one or more classes (in all 36 classes) and each dataset to printed must also be assigned classes. The printer routines selects datasets for printing in a very similar way as initiators selects jobs for executions. Use S.ST option of ISPF menu to view the output dataset.
The SYSOUT parameter can assign this class, known as sysout or output class, to a dataset. Such datasets are called sysout or output datsets.
General Syntax
SYSOUT=(class| *) keyword parameter
Class – Identifies the sysout class of the dataset from A to Z and 0 to 9.
*- Indicates that the same class used in the MSGCLASS parameter of the JOB statement (or the installation-defined default, if MSGCLASS parameter is omitted) is to be used.
E.g 1. sysout=a
E.g 2 //sysprint dd sysout=*
This DD statement is used for printing system messages generated by JES2 or JES3. Each step must have SYSPRINT DD statement. Absence will cause “ SYSPRINT DD STATEMENT MISSING” message in the sysout.
E.g 3 //sysout dd sysout=* (or any sysout class may be assigned)
This DD statement is used when you have COBOL DISPLAY clause in your program.
Concatenation
Concatenating Datasets
At times, program may have to read in sequence several input datasets as if they were one. This can accomplished without physically putting the data in one datasets. This is done by concatenating the datasets in JCL code with comparable DCB characteristics without programming changes.
Note that only sequential and partitioned datasets can be concatenated. For sequential datasets, the maximum number of concatenations is 255 and for PDS it is 16. Concatenation has meaning only for sequential processing.
E.g 1. Concatenation of physical sequential files.
//dd1 dd dsn=da0001t.pcs.group1,disp=shr
// dd dsn=da0001t.pcs.group2,disp=shr
// dd dsn=da0001t.pcs.group3,disp=shr
E.g 2. Concatenation of partitioned datasets.
//dd1 dd dsn=da0001t.pds1.group1,disp=shr
// dd dsn=da0001t.pds2.group2,disp=shr
// dd dsn=da0001t.pds3.group3,disp=shr
There are number of rules and restrictions for concatenations :
1. The first concatenation is the only one with a ddname.
2. The logical record length and the record format of concatenated datasets must be the same. However, the blocksizes need not be.
3. The blocksize of the first concatenation must be greater than or equal to blocksizes of all subsequent concatenation. Violation of this rule results in S001-04 ABEND failure. This is true for DFP Version 2.3. For version DFP 2.4, one can concatenate datasets in any sequence, but for the first concatenation code the DCB parameter with the largest blocksize of all the concatenations.
E.g. Assume that in the JCL below, the first concatenation has a blocsize of 800, the second a blocksize of 800- and the third a blocksize of 23400.
//infile dd dsn=da0001t.pcs.group1,disp=shr,dcb=23400
// dd dsn=da0001t.pcs.group2,disp=shr
// dd dsn=da0001t.pcs.group3,disp=shr
4. Both sequential datasets and partitioned datasets can be concatenated, but not with each other – sequential with sequential and partitioned with partitioned only. Member of a PDS is treated as sequential dataset and thus can be concatenated with sequential dataset.
E.g
//in dd dsn=da0001t.empfile,disp=shr
// dd dsn=da0001t.pcs.data(emp),disp=shr
5. Disk as well as tape datasets can be concatenated but not with each other. Only like devices should be concatenated, disk with disk and tape with tape.
DUMMY Parameter
The DUMMY parameter is a positional parameter. At times, one might want to execute a program but suppress read or write operations in certain jobs, For example., not print a report. At other times, one might want to test a program without actually processing data.
The DUMMY parameter specifies that :
• No device or external storage be allocated.
• No disposition processing is performed.
• No input or output operations are performed for sequential access methods.
Remark :
1 DCB information is established. Generally used during testing process and in procedures. Instead of using DUMMY, one may use DSN=NULLFILE. It differs from DUMMY by virtue of its position. It is a keyword parameter.
E.g //DD1 DD DSN=NULLFILE
2 When an attempt to dummy a PDS is made will cause an S013-64 ABEND failure.
3 The DCB parameter may be required while coding DUMMY. Failure to do so may cause an S013-10 ABEND failure.
4 DUMMY provides a safe way to eliminate I/O activity when required.
The JOBLIB DD Statement
The JOBLIB statement identifies the program library (load library) where the programs to be executed throughout the job resides. It must be placed between the JOB and the first EXEC statement.
E.g :
//da0001ta job,la2719,……
//joblib dd dsn=da0001t.lib.loadlib,disp=shr
//s1 exec pgm=proga
//s2 exec pgm=progb
Expanation : PROGA (and PROGB) is expected to reside in DA0001T.LIB.LOADLIB as a member of a library and the system searches the directory. If not found will search certain predefined libraries and the S806-04 ABEND failure occurs.
Remark :
A JOBLIB DD statement can have several concatenations (max: 16)
E.g
//da0001ta job,la2719,……
//joblib dd dsn=da0001t.lib.loadlib,disp=shr
// dd dsn=da0001t.lib1.loadlib,disp=shr
// dd dsn=da0001t.prod.loadlib,disp=shr
//s1 exec pgm=proga
Explanation : All concatenations may be searched to locate a program. If, however, the program is found in a concatenation other than the last one, other concatenations will not be used. Note that, if a duplicate names exist in different concatenations, the user can decide which one is to be executed by determining the sequence of the concatenations.
The STEPLIB STATEMENT
The STEPLIB statement identifies the program library (load library) where the program to be executed for the step where STEPLIB resides. It can be placed anywhere after the EXEC statement.
E.g 1:
//da0001ta job,la2719,……
//s1 exec pgm=proga
//steplib dd dsn=da0001t.lib.loadlib,disp=shr
//s2 exec pgm=progb
//steplib dd dsn=da0001t.lib.loadlib1,disp=shr
Explanation : Program PROGA is expected to reside in DA0001TA.LIB.LOADLIB as a member of the library. If not found, will search certain predefined libraries and the S806-04 ABEND failure occurs.
E.g 2:
//da0001ta job,la2719,……
//joblib dd dsn=da0001t.lib.loadlib1,disp=shr
//s1 exec pgm=proga
//s2 exec pgm=progb
//steplib dd dsn=da0001t.lib.loadlib,disp=shr
//s3 exec pgm=progc
A STEPLIB DD statement has the effect of negating the JOBLIB DD statement for a particular step.
STORAGE DUMP
When a step encounters an ABEND failure, it is often advantageous to request a virtual storage dump, which can then be helpful in determining the cause of an ABEND. To request a storage dump, one of the following three DD statements must be included in the step :
• A SYSUDUMP DD statement
• A SYSMDUMP DD statement
• A SYSABEND DD statement
//sysudump dd sysout=*
All virtual storage allocated to your program i.e user region of job’s address space. It is a formatted dump. SYSUDUMP usually writes to sysout. It can, however, write to a disk dataset, providing a way to preserve the SYSUDUMP information for later viewing and analysis.
//sysudump dd dsn=da0001t.dumpfile,space=(trk,(0,5),rlse),
// disp=(,delete,catlg),unit=sysda
No DCB is required.
Remark :
SYSUDUMP DD statement is more often used.
//sysmudump dd sysout=*
This is same as SYSUDUMP DD statement except for the fact that the dump is nonformatted. This type of dump is very difficult to analyze unless it is saved on a disk and then processed by the PRDUMP service aid.
SYSMDUMP is seldom used.
//sysabend dd sysout=*
When a SYSUDUMP DD statement is included in a step which ABEND’s, a formatted virtual storage dump will be provided. This dump will also include information about the failed step, as well as most of the MVS storage-resident information which is of no use to the average user. SYSABEND is intended for system programmer.
Remark :
1 If neither a SYSUDUMP nor a SYSMDUMP nor a SYSABEND statement is coded wihin a JCL of an ABENDing step, a small amount of information is provided. This information is seldom useful in resolving the problem that caused the ABEND failure.
2 If more than one of the above statements is included in the JCL of a step, only the last one will be used. The previous ones will be ignored.
//s1 exec pgm=ass1
//sysabend dd sysout=*
//sysudump dd sysout=*
Note that SYSUDUMP will be in use.
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5. PROCEDURE
• There are two types of procedures :
- Catalogue Procedures
- InStream Procedures
• CATALOGUED PROCEDURE is a member of a PDS which is often refered to as procedure library or PROCLIB.
• INSTREAM PROCEDURES contained within job's input stream.
INVOKING A PROCEDURE
//PR EXEC ABC
OR
//PR EXEC PROC = ABC
RESTRICTIONS
- max 255 steps
• The following are not permitted to reside in a procedure :
- JOB Statement
- An EXEC statement invoking a procedure
- JOBLIB
- JOBCAT
- DD * or DATA
- // null statement
- A PEND statement
Common Rules for EXEC & DD Statement to Override for JCL Procedures
• A parameter can be replaced, added or nullified
• When replacing an existing parameter, the overriding parameter must be specified in its complete format. DCB is an exception
• An overriding parameter replaces the same parameter, if it exists. It is added to the statement if it does not exist.
• A syntactical JCL error inside a procedure cannot be corrected by overriding the erroneous parameter.
• To nullify an existing parameter "parameter" = must be coded
• To override any parameters in an concatenation other than the first one, the following must be coded :
//stepname.ddname DD
// DD
// .
// .
// DD overriding parameters
• To add an entire DD statement
// stepname.ddname DD complete parameter field.
RULES FOR EXEC STATEMENT OVERRIDING
• To override any parameter in a DD statement an independent DD statement must be supplied in the following format :
• The sequence of overriding DD statements must be the same as the sequence of the corresponding overridden statements. However, parameters within a DD statement need not be overridden in sequence.
• An additional DD statement must be the last one in a step's overriding statements.
• To override an EXEC parameter, " parameter.stepname=value" must be coded when adding or replacing a parameter and "parameter.stepname=" must be coded when nullifying a parameter.
• The PGM parameter cannot be overridden
• All overriding EXEC parameters must be coded in the EXEC statement that invokes the procedure.
• All overrides to EXEC parameters must be completed before overriding parameters in a subsequent step.
procedure lam
//S1 EXEC PGM=ED, PARM=(A,B,C,E)
// REGION=900K, TIME = (5,30)
//STEPLIB DD DSN=DEV.LOADLIB,DISP=SHR
//IN1 DD DSN=USER1.FILE2,DISP=SHR
//IN2 DD DSN=USER1.FILEX,DISP=OLD
// UNIT=TAPE, VOL=SER=000101
//REP DD SYSOUT =*,
//OUT DD DSN=USER1.PLA,DISP=(,CTLG,DELETE),
// UNIT=SYSDA, VOL=SER=BS3003
// SPACE=(CYL,(20.5),DCB=(BLKSIZE=4000,
// LRECL=80, RECFM=FB)
Required in step S1:
a) PARM must be (A,B,C,D) and TIME nullified
b) In IN1, DSN must be USER1.FILE3
c) IN2 must retrieve USER1.FILEX as a cataloged dataser
d) In OUT, BLKSIZE must be 23440
//S2 EXEC PGM=FORM, REGION=900K
//INA DD DSN=USER1.PLA,DISP=SHR
// DD DSN=USER1.F226,DISP=SHR
// DD DSN=USER1.F232,DISP=SHR
// DD DSN=USER1.F118,DISP=SHR
//OUTA DD DSN=USER.F323,DISP=(,CATLG,DELETE),
// UNIT=TAPE, VOL=SER=001110
// DCB=BLKSIZE=32700, LRECL=100,
// RECFM=FB)
//PRNT DD SYSOUT=*
Required in Step S2 :
a) COND = (0,LT) must be coded
b) In INA DSN in the third concatenation must be USER1.F228
c) In DD statement OUTA, UNIT be SYSDA
d) An entire DD statement :
//STEPLIB DD DSN=DEV.LOADLIB,DISP=SHR
must be coded.
//S3 EXEC PGM=REPO,REGION = 400K, COND=(O,LT)
//1N3 DD DSN=USER1.F333, DISP=OLD
//OUT3 DD DSN=USER1.F111,DISP=(,CRLG,DELETE),
// UNIT=SYSDA, VOL=SER=DEVO12,
// SPACE=(CYL,(50,15),RLSE),
// DC3=(BLKSIZE=23440,LRECL=80,RECFM=FB)
//PRINT DD SYSOUT =*
//
Required in Step S3 :
a) EVEN must be added to the COND parameter
b) In DD statement OUT3, RLSE must be removed from the SPACE parameter must be nullified.
SOME TYPICAL EXAMPLES
Example 1:
//S1 EXEC PGM=ONE
//OUT1 DD DSN=U1.S1,
// DISP=(,CTLG, DELETE),
// UNIT=TAPE
// DCB=(BLKSIZE=32700)
Required
OUT1 must be dummied
Override
//S.OUT1 DD DUMMY
Regardless of the contents, no other parameters are needed.
SOME TYPICAL EXAMPLES
Example 2 :
//S1 EXEC PGM=ONE
//IN1 DD DSN=U1.B1,DISP=SHR
// DD DSN=U2.B2,DISP=SHR
// DD DSN=U3.B3,DISP=SHR
Required
Second concatenation of INI must be dummy
Override
//S1.INI DD
DD DSN=U1.B3
DD DUMMY
Example 3:
//S1 EXEC PGM=ONE
//CNTL DD DSN=U1.CNTLIB(S1), DISP=SHR
Required
DD statement CNTL must be //CNTL DD*
Override
//S1.CNTL DD*
Regardless of the contents DD * will override all.
Example 4 :
//S1 EXEC PGM = ONE
//OVT4 DD DSN=U1.D1,DISP=NEW
// DISP=SYSDA,VOL=SER=TEST26,
// SPACE=CTRK,(500,50)),
// DCB=(BLKSIZE=23400,
// LRECL=100,RECFM=FB)
Required
DCB parameter must be eliminated
Override
//S1.OUT4 DD DCB=(BLKSIZE=LRECL=RECFM)
SYMBOLIC PARAMETERS & SYMBOLIC OVERRIDES
• Symbolic overrides can be used only when symbolic parameters have been coded inside the procedure
• A symbolic parameter is a name preceded by an ampersand (&)
• A symbolic parameter can be coded in place of any parameter, part of a parameter in the parameter field of an EXEC, DD or OUTPUT statement.
SYMBOLIC PARAMETER
Example 1 :
//S1 EXEC PGM=BL
//IN DD DSN=&H1..INFILE,DISP=SHR
//OUT DD DSN=&HQ..OUTFILE,DISP=,CATLG,DELETE),
// UNIT=SYSDA, DCB=(BLKSIZE=32700)
//PSK EXEC BLTX,HQ=PROD
- First period works as delimiter
Example 2 :
Procedure BLTX
//S1 EXEC PGM=BL
//IN DD DSN=&HQ…INFILE,DISP=SHR
//OUT DD DSN=&HQ…OUTFILE,DISP=,CATLG,DELETE
// UNIT=SYSDA,DCB(=BLKSIZE=32700)
//PSK EXEC BLTX,HQ='PROD.'
SYMBOLIC OVERRIDING
RULES FOR SYMBOLIC OVERRIDING
• An EXEC statement keyword (TIME, REGION etc.) cannot be used as a symbolic parameter.
• A symbolic override in either the EXEC or PROC statement that has no corresponding parameter in the procedure will result in a 'SYMBOL NOT DEFINED' JCL error.
• If a symbolic and a regular override conflict, the regular override always prevails.
• A symbolic parameter which is immediately followed by an alphabetic, numeric or national character must have a period at its end.
• A symbolic parameter can be coded many times in a procedure. When substitution occurs, all the occurrences will receive the same value.
• When nothing must be substituted for a symbolic parameter, "symbolic-override=' must be coded in the EXEC or PROC statement.
PROCEDURE SSP
//S1 EXEC PGM = P1, PARM = &PEL
Assume possible values that the PARM parameter can assume are ALD, BLD, CLD, etc.
//S1 EXEC PGM=P1, PARM = &PELLD
This will not work
Procedure SSP can be coded as
//S1 EXEC PGM=P1, PARM = PEL.LD
Now if the procedure is invoked
//A EXEC SSP, PEL=F
Substitution results in
//S1 EXEC PGM=P1, PARM = FLD
//S1 EXEC PGM = P1, PARM = &PEL
Example 1 :
//A EXEC SSP, PEL=FLD
Substitution results in
//S1 EXEC PGM=P1, PARM=FLD
Example 2 :
//B EXEC SSP, PEL = FLD, TIME = (5, 10)
substitution results in
//S1 EXEC PGM = P1, PARM=FLD, TIME = (5,10)
PROCEDURE SWP
//ABC PROCR=800K, Q=AUX, U=TAPE
//S1 EXEC PGM=P2, REGION=&R
//IN DD DSN=&Q..FILEX, DISP=SHR
//OUT DD DSN=&Q..FILEY, DISP=(,CATLG)
// UNIT = &U
//A EXEC SWP, Q=MAX
Substitution results in
//S1 EXEC PGM=P2, REGION=800K
//IN DD DSN=MAX.FILEX, DISP=SHR
//OUT DD DSN=MAX.FILEY, DISP=(,CATLG),
// UNIT =TAPE
THE PROC STATEMENT
• The purpose of the PROC statement is to contain symbolic override defaults.
• When a procedure is executed, the system will substitute symbolic parameters using symbolic overrides coded in the EXEC statement.
• For those symbolic overrides not found in the EXEC statement, the default symbolic overrides in the PROC statement will be used.
IN-STREAM PROCEDURES
• An in-stream procedures is a part of a job's input stream and exists only for the duration of the job.
• The PROC statement in an in-stream procedure is mandatory and serves two functions -
a) It signals the beginning of in-stream procedure
b) It contains default symbolic overrides.
• The PEND statement must be coded in an in-stream procedure to provide a delimiter
Remark :
1) A PROC statement in a catalogued procedure is optional. The only reason it is required is to contain default symbolic overrides.
Example :
//da0001ta JOB la2719,pcs,msgclass=A,
// msglevel=(1,1,),notify=da0001t
//* Instream prosedure
//procbr14 proc
//s1 exec pgm=iefbr14
//sysprint dd sysout=*
//dd1 dd dsn=da0001t.temp,
// disp=(old,delete)
// pend
//*
//step1 exec proc=procbr14
//s1.dd1 dd dsn=da0001t.temp1,
// disp=(,catlg,delete), unit=sysda,
// space=(trk,(2,1)),
// dcb=(1recl=80,recfm=fb,blksize=800)
//
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- Catalogue Procedures
- InStream Procedures
• CATALOGUED PROCEDURE is a member of a PDS which is often refered to as procedure library or PROCLIB.
• INSTREAM PROCEDURES contained within job's input stream.
INVOKING A PROCEDURE
//PR EXEC ABC
OR
//PR EXEC PROC = ABC
RESTRICTIONS
- max 255 steps
• The following are not permitted to reside in a procedure :
- JOB Statement
- An EXEC statement invoking a procedure
- JOBLIB
- JOBCAT
- DD * or DATA
- // null statement
- A PEND statement
Common Rules for EXEC & DD Statement to Override for JCL Procedures
• A parameter can be replaced, added or nullified
• When replacing an existing parameter, the overriding parameter must be specified in its complete format. DCB is an exception
• An overriding parameter replaces the same parameter, if it exists. It is added to the statement if it does not exist.
• A syntactical JCL error inside a procedure cannot be corrected by overriding the erroneous parameter.
• To nullify an existing parameter "parameter" = must be coded
• To override any parameters in an concatenation other than the first one, the following must be coded :
//stepname.ddname DD
// DD
// .
// .
// DD overriding parameters
• To add an entire DD statement
// stepname.ddname DD complete parameter field.
RULES FOR EXEC STATEMENT OVERRIDING
• To override any parameter in a DD statement an independent DD statement must be supplied in the following format :
• The sequence of overriding DD statements must be the same as the sequence of the corresponding overridden statements. However, parameters within a DD statement need not be overridden in sequence.
• An additional DD statement must be the last one in a step's overriding statements.
• To override an EXEC parameter, " parameter.stepname=value" must be coded when adding or replacing a parameter and "parameter.stepname=" must be coded when nullifying a parameter.
• The PGM parameter cannot be overridden
• All overriding EXEC parameters must be coded in the EXEC statement that invokes the procedure.
• All overrides to EXEC parameters must be completed before overriding parameters in a subsequent step.
procedure lam
//S1 EXEC PGM=ED, PARM=(A,B,C,E)
// REGION=900K, TIME = (5,30)
//STEPLIB DD DSN=DEV.LOADLIB,DISP=SHR
//IN1 DD DSN=USER1.FILE2,DISP=SHR
//IN2 DD DSN=USER1.FILEX,DISP=OLD
// UNIT=TAPE, VOL=SER=000101
//REP DD SYSOUT =*,
//OUT DD DSN=USER1.PLA,DISP=(,CTLG,DELETE),
// UNIT=SYSDA, VOL=SER=BS3003
// SPACE=(CYL,(20.5),DCB=(BLKSIZE=4000,
// LRECL=80, RECFM=FB)
Required in step S1:
a) PARM must be (A,B,C,D) and TIME nullified
b) In IN1, DSN must be USER1.FILE3
c) IN2 must retrieve USER1.FILEX as a cataloged dataser
d) In OUT, BLKSIZE must be 23440
//S2 EXEC PGM=FORM, REGION=900K
//INA DD DSN=USER1.PLA,DISP=SHR
// DD DSN=USER1.F226,DISP=SHR
// DD DSN=USER1.F232,DISP=SHR
// DD DSN=USER1.F118,DISP=SHR
//OUTA DD DSN=USER.F323,DISP=(,CATLG,DELETE),
// UNIT=TAPE, VOL=SER=001110
// DCB=BLKSIZE=32700, LRECL=100,
// RECFM=FB)
//PRNT DD SYSOUT=*
Required in Step S2 :
a) COND = (0,LT) must be coded
b) In INA DSN in the third concatenation must be USER1.F228
c) In DD statement OUTA, UNIT be SYSDA
d) An entire DD statement :
//STEPLIB DD DSN=DEV.LOADLIB,DISP=SHR
must be coded.
//S3 EXEC PGM=REPO,REGION = 400K, COND=(O,LT)
//1N3 DD DSN=USER1.F333, DISP=OLD
//OUT3 DD DSN=USER1.F111,DISP=(,CRLG,DELETE),
// UNIT=SYSDA, VOL=SER=DEVO12,
// SPACE=(CYL,(50,15),RLSE),
// DC3=(BLKSIZE=23440,LRECL=80,RECFM=FB)
//PRINT DD SYSOUT =*
//
Required in Step S3 :
a) EVEN must be added to the COND parameter
b) In DD statement OUT3, RLSE must be removed from the SPACE parameter must be nullified.
SOME TYPICAL EXAMPLES
Example 1:
//S1 EXEC PGM=ONE
//OUT1 DD DSN=U1.S1,
// DISP=(,CTLG, DELETE),
// UNIT=TAPE
// DCB=(BLKSIZE=32700)
Required
OUT1 must be dummied
Override
//S.OUT1 DD DUMMY
Regardless of the contents, no other parameters are needed.
SOME TYPICAL EXAMPLES
Example 2 :
//S1 EXEC PGM=ONE
//IN1 DD DSN=U1.B1,DISP=SHR
// DD DSN=U2.B2,DISP=SHR
// DD DSN=U3.B3,DISP=SHR
Required
Second concatenation of INI must be dummy
Override
//S1.INI DD
DD DSN=U1.B3
DD DUMMY
Example 3:
//S1 EXEC PGM=ONE
//CNTL DD DSN=U1.CNTLIB(S1), DISP=SHR
Required
DD statement CNTL must be //CNTL DD*
Override
//S1.CNTL DD*
Regardless of the contents DD * will override all.
Example 4 :
//S1 EXEC PGM = ONE
//OVT4 DD DSN=U1.D1,DISP=NEW
// DISP=SYSDA,VOL=SER=TEST26,
// SPACE=CTRK,(500,50)),
// DCB=(BLKSIZE=23400,
// LRECL=100,RECFM=FB)
Required
DCB parameter must be eliminated
Override
//S1.OUT4 DD DCB=(BLKSIZE=LRECL=RECFM)
SYMBOLIC PARAMETERS & SYMBOLIC OVERRIDES
• Symbolic overrides can be used only when symbolic parameters have been coded inside the procedure
• A symbolic parameter is a name preceded by an ampersand (&)
• A symbolic parameter can be coded in place of any parameter, part of a parameter in the parameter field of an EXEC, DD or OUTPUT statement.
SYMBOLIC PARAMETER
Example 1 :
//S1 EXEC PGM=BL
//IN DD DSN=&H1..INFILE,DISP=SHR
//OUT DD DSN=&HQ..OUTFILE,DISP=,CATLG,DELETE),
// UNIT=SYSDA, DCB=(BLKSIZE=32700)
//PSK EXEC BLTX,HQ=PROD
- First period works as delimiter
Example 2 :
Procedure BLTX
//S1 EXEC PGM=BL
//IN DD DSN=&HQ…INFILE,DISP=SHR
//OUT DD DSN=&HQ…OUTFILE,DISP=,CATLG,DELETE
// UNIT=SYSDA,DCB(=BLKSIZE=32700)
//PSK EXEC BLTX,HQ='PROD.'
SYMBOLIC OVERRIDING
RULES FOR SYMBOLIC OVERRIDING
• An EXEC statement keyword (TIME, REGION etc.) cannot be used as a symbolic parameter.
• A symbolic override in either the EXEC or PROC statement that has no corresponding parameter in the procedure will result in a 'SYMBOL NOT DEFINED' JCL error.
• If a symbolic and a regular override conflict, the regular override always prevails.
• A symbolic parameter which is immediately followed by an alphabetic, numeric or national character must have a period at its end.
• A symbolic parameter can be coded many times in a procedure. When substitution occurs, all the occurrences will receive the same value.
• When nothing must be substituted for a symbolic parameter, "symbolic-override=' must be coded in the EXEC or PROC statement.
PROCEDURE SSP
//S1 EXEC PGM = P1, PARM = &PEL
Assume possible values that the PARM parameter can assume are ALD, BLD, CLD, etc.
//S1 EXEC PGM=P1, PARM = &PELLD
This will not work
Procedure SSP can be coded as
//S1 EXEC PGM=P1, PARM = PEL.LD
Now if the procedure is invoked
//A EXEC SSP, PEL=F
Substitution results in
//S1 EXEC PGM=P1, PARM = FLD
//S1 EXEC PGM = P1, PARM = &PEL
Example 1 :
//A EXEC SSP, PEL=FLD
Substitution results in
//S1 EXEC PGM=P1, PARM=FLD
Example 2 :
//B EXEC SSP, PEL = FLD, TIME = (5, 10)
substitution results in
//S1 EXEC PGM = P1, PARM=FLD, TIME = (5,10)
PROCEDURE SWP
//ABC PROCR=800K, Q=AUX, U=TAPE
//S1 EXEC PGM=P2, REGION=&R
//IN DD DSN=&Q..FILEX, DISP=SHR
//OUT DD DSN=&Q..FILEY, DISP=(,CATLG)
// UNIT = &U
//A EXEC SWP, Q=MAX
Substitution results in
//S1 EXEC PGM=P2, REGION=800K
//IN DD DSN=MAX.FILEX, DISP=SHR
//OUT DD DSN=MAX.FILEY, DISP=(,CATLG),
// UNIT =TAPE
THE PROC STATEMENT
• The purpose of the PROC statement is to contain symbolic override defaults.
• When a procedure is executed, the system will substitute symbolic parameters using symbolic overrides coded in the EXEC statement.
• For those symbolic overrides not found in the EXEC statement, the default symbolic overrides in the PROC statement will be used.
IN-STREAM PROCEDURES
• An in-stream procedures is a part of a job's input stream and exists only for the duration of the job.
• The PROC statement in an in-stream procedure is mandatory and serves two functions -
a) It signals the beginning of in-stream procedure
b) It contains default symbolic overrides.
• The PEND statement must be coded in an in-stream procedure to provide a delimiter
Remark :
1) A PROC statement in a catalogued procedure is optional. The only reason it is required is to contain default symbolic overrides.
Example :
//da0001ta JOB la2719,pcs,msgclass=A,
// msglevel=(1,1,),notify=da0001t
//* Instream prosedure
//procbr14 proc
//s1 exec pgm=iefbr14
//sysprint dd sysout=*
//dd1 dd dsn=da0001t.temp,
// disp=(old,delete)
// pend
//*
//step1 exec proc=procbr14
//s1.dd1 dd dsn=da0001t.temp1,
// disp=(,catlg,delete), unit=sysda,
// space=(trk,(2,1)),
// dcb=(1recl=80,recfm=fb,blksize=800)
//
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