DLBL
assgn sysO 1 0 d
dlbl ijsysuc d dsn mycat (perm sys010 identifies the job (user) catalog, MYCAT, for the terminal session.
assgn sys100 e dlbl intest1 e dsn test case (vsam sys100 identifies a VSAM file to be used in a program. It is cataloged in the
job catalog, MYCAT. assgn sys101 f
dlbl cat3 f dsn testcat {cat ijsysct sys101 identifies an additional user catalog, which has an entry in the master
catalog. Since a job catalog is in use, you must use the CAT option to
indicate that another catalog, in this case the master catalog, should
be used.
dlbl infile f dsn test input (cat cat3 sys101 identifies an input file cataloged in the user catalog TESTCAT, which
was identified with a ddname of CAT3 on the DLBL The selection of a VSAM catalog for AMSERV jobs and VSAM programs
running in CMS is summarized in Figure 7. IS THE CAT OPTION SPECIFIED ON THE
DLBL COMMAND ? NO I IS THERE A
DLBL ACTIVE FOR IJSYSUC ? NO USE THE
MASTER CATALOG YES YES USE THE CATALOG DEFINED BY
THAT DDNAME USE THE JOB CATALOG Figure 1. Determining Which VSAM Catalog to Use Section 2. CMS Commands 67

DLBL
1. You must use the DLBL command to identify all access method
services input and output files, and to identify all VSAM input and
output files referenced in programs. For all other file definitions, including os or :MS disk files
referenced in programs that use VSAM data management, you must use
the FILEDEF command.
2. A DLBL ddname may have a maximum of seven characters. If you have
ddnames in your programs that are eight characters long, only the
first seven characters are processed when the programs are executed
in CMS. If you have two ddnames with the same first seven
characters and you attempt to execute this program in eMS, you will
receive an open error when the second file is opened. You should
recompile these programs providing unique seven-character ddnames.
3. If you release a disk for which you have a DLBL definition in
effect, you should clear the DLBL definition before you execute a VSAM program or an AMSERV command. CMS checks that all disks for
which there are DLBL definitions are accesse1, and issues error
message DMSSTT069E if any are not. You must specify extent information
when you use the access method services control statements DEFINE SPA:E, DEFINE MASTERCA!ALOG, DEFINE USERCATALOG, DEFINE CLUSTER (UNIQUE); or
when you use the IMPORT or IMPORTRA functions for a unique file. Space allocation is made only for primary allocation amounts. When you enter the EXTENT option of the DLBL command, you are
promoted to enter the disk extents for the specified file. You must
enter extent information in accordance with the following rules: • You must specify the starting track number and number of tracks for
each as follows: 10 38
This extent allocates 38 tracks, beginning with the 19th track, on a
3330 device. • All extents must begin and end on cylinder boundaries, regardless of
whether the AMSERV file contains extent information in terms of
cylinders, tracks, or records. • Multiple extent entries may be entered commas or on different lines. Commas
ignored.
on a single line separated by
at the end of a line are • Multiple extents for the same volume must be entered in numerically
ascending order; for example: 20 400, 6 00 80 These extents are valid for a 2314 device. • When you enter multivolume extents, you must specify the mode letter
for extents on additional disks; extents for each disk must be
entered consecutively. For example:
68 IBM VM/37Q CMS Command and Macro Reference