If you formatted the minidisk yourself, you know what label you assigned
it; if not, you can find out the label assigned to the disk by issuing
the CMS command:
query search
The response might be: USR191 VSAM03 SYS109 SYS19E 191 A 333 C 190 S 19E Y/S R/W R/i - os R/O R/O Use the volume label VSAM03 in the MASTCAT AMSERV file:
DEFINE MASTERCATALOG -
(NAME (MASTCAT)­ VOLUME (VSAM03) - CYL (4) -
FILE (IJ SYSCT) To find out what extents on this minidisk you can allocate for VSAM, use
the LISTDS command with the FREE option:
listds d (free
The response from LISTDS might look like this: FREESPACE INFORMATION FOR 'D' DISK: CYL-HD(RELTRK) TO CYL-HD(RELTRK) TRACKS 000 01 1 000 09 9 9 000 11 11 029 18 569 560 From this response, you can see that the VTOC is located on the first
cylinder, so you can allocate cylinders 1 through 29 for VSAM: dlbl ijsysct c dsn mastcat (perm extent DMSDLB331R ENTER EXTENT SPECIFICATIONS: 19 551
(null line)
After entering the extents, in tracks, g1v1ng the relative track number
of the first track to be allocated followed by the number of tracks, you
must enter a null line to complete the command. (A null line is required
because, when you enter multiple extents, entries may te placed on more
than one line.) Now you can issue the AMSERV command:
amserv mastcat
A Ready message with no return code indicates that the master catalog is
defined. You do not need to reissue the DLBL command in order to
identify the master catalog for additional AMSERV functions. You can use the AMSERV command to define private catalogs and spaces for
them. The procedures for determining what space you can allocate are the
same as those outlined in the example of defining a master catalog.
To define a user catalog, you can assign any ddname you want: 200 IBM VM/370 eMS User's Guide

access 199 e
listds e (free
dlbl cat1 e dsn private cat1 (extent
amserv usercat
The file USERCAT AMSERV might contain the following:
DEFINE USERCATALOG - (NAME (PRIVATE.CAT1) -
FILE (CAT1)- CYL (4) - VOLUME (OSVSAM) - CATALOG (MASTCAT) After this AMSERV command has completed successfully you can use the
catalog PRIVATE.CAT1. When you define a file cataloged in it, you
identify it using the CAT option on the DLBL command:
dlbl file2 c dsn ? (cat cat1 Or, you can define it as a job catalog.
During a terminal session, you may be referencing the same private
catalog many times. If this is the case, you can identify a job catalog by using the ddname IJSYSUC. Then, that catalog is searched during all
subsequent jobs, unless you override it using the CAT option when you
use the DLBL command to define a file.
If you defined a user catalog (IJSYSUC) for a terminal session and
you use the AMSERV command to access a 1SAa file, the user catalog takes
precedence over the master catalog. This means that for files that
already exist, the job catalog is searched. When you define a cluster,
it is cataloged in the job catalog, rather than in the master catalog,
unless you use the CAT option to override it. CMS never searches more
than one VSAM catalog. You should use the CAT option to name a catalog when the AMSERV file
you are executing references, with the CATALOG parameter, a catalog that
is not defined either as the master catalog or as a user catalog.
If you want to use additional catalogs during a terminal session, you
first define them just as you would any other VSAM file:
dlbl mycat2 f dsn private cat2 (vsam
Then, when you enter the DLBL command for the VSAM file that is
cataloged in PRIVATE.CAT2 use the CAT option to refer to the ddname of
the catalog:
dlbl input f dsn input file (cat mycat2
If you want to stop using a job catalog defined with the ddnaBe IJSYSUC, you can clear it using the CLEAR option of the DLEL command: Section 10. using Access Method Services and VSAM 201