5. LISTCAT

LISTCAT’s basic function is to list information about VSAM and NONVSAM objects. With LISTCAT you can also view password and security information, usage statistics, space allocation information, creation and expiration dates etc.
Format 1:

LISTCAT ENTRIES(entryname) options

Options are :
• HISTORY
• VOLUME
• ALLOCATION
• ALL

ENTRIES (ENT) requires you to specify each level of qualification, either explicitly or implicitly, using an asterisk as a wild card character.

Examples:

LISTCAT
ENT(DA0001T.VSAM.KSDS.CLUSTER) -
CLUSTER -
ALL -


Example 5.1 LISTCAT

The above command will only display the base cluster


LISTCAT
ENT(DA0001T.VSAM.KSDS.CLUSTER) -
DATA -
ALL -



The above command will only display the data component








LISTCAT
ENT(DA0001T.VSAM.KSDS.CLUSTER) -
ALL



The above command will display all catalog information.


//STEP1 EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=*
//SYSIN DD *
LISTCAT -
ENTRIES(DA0001T.LIB.KSDS.CLUSTER) ALL
/*


Format 2:

LISTCAT LEVEL(level) options

LEVEL by definition lists all lower levels. VSAM assumes that qualifier to be the high-level qualifier and list every entry with that high level qualifier .

Example


LISTCAT LVL(DA0001T.*.KSDS) ALL


The above will list all entries with DA0001T as high level qualifier , anything in the second-level qualifier and KSDS in the third-level qualifier . That is it would list DA0001T.ABC.KSDS and DA0001T.TEST.KSDS.AIX, DA0001T.TEST.KSDS.DATA .

To execute LISTCAT from TSO prompt

LISTCAT ENTRIES (LIB.KSDS.CLUSTER) ALL


If you analyze the output of the LISTCAT command there is ALLOCATION information which shows two fields HURBA and HARBA.

High-Used-RBA (HURBA)points to the end of the data. High-Allocated-RBA (HARBA)is the highest byte that can be used.

HIGH-ALLOC-RBA indicates the Relative Byte Address(plus 1) of the last allocated data control area. This value reflects the total space allocation for the data component.
HIGH-USED-RBA indicates the Relative Byte Address(plus 1) of the last used data control area. This value reflects the portion of the space allocation that is actually filled with data records.

There are actually to HURBAs one in the VSAM control block of the cluster and one in the catalog entry for the cluster.
You can write application programs (in COBOL, PL/I Assembler Language, in CICS) and use the statements provided by these languages to write and read VSAM datasets

















Figure 5.1 HURBA and HARBA

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