dlbl filel b (extent DMSDLB331R ENTEF EXTENT SPECIFICATIONS: 100 60, 400 80, 60 40 d 200 100 c 400 100 c
(null line)
DLBL
specifies extents on disks accessed at modes B, C, and D. Since B is
the mode specified on the DLBL command line, it does not qeed to be
respecified along with the extent information. A DASD volume must be mounted and accessed for each mode referenced
in an extent. When you are finished entering extent information, you must enter a
null line to terminate the DLBL command sequence. If you do not, an erroL may result and you will have to reenter the entire DLBL command.
If you make any error entering the extents, you must reenter all the
extent information.
The OLBL command does not check the extents to see if they are on cylindeL boundaries or that they are entered in the proper If
you do not enter them correctly, the access method services DEFINE
function terminates with an error. CMS assigns sequence numbers to the extents according to the order in
which they were entered. These sequence numbers are listed when you use
the LISTDS command with the EXTENT option. When you want to execute a program
or use access method services to reference an existing multivolume VSAM data set, you must use the MULT option on the DLBL command that
identifies the file. When you use the MULT option, you are prompted to enter additional
disk mode letters, as follows:
dlbl infile c (mult DMSDLB330R ENTER VOLUME SPECIFICATIONS: d, e, f
g
(null line)
The above example identifies a file that has extents on disks accessed
at modes C, D, E, P, and G. The rules for entering multiple extents are: All disks must be mounted and accessed when you issue the DLBL
command. You must not repeat the mode letter of the disk that is entered on
the DLBL command line (C in the above example) If you enter more than one mode letter on a line, they must be
separated by commas; trailing commas on a line are ignored. A maximum of nine disks may be specified; you do not need to specify
them in alphabetical order. You must enter a null line to terminate the
finished entering extents; if not, an error may re-enteL the entire command sequence.
command when
result and
you are
you must Section 2. Commands 69
DL BL There are two special ddnames you must use to
identify a VSAM master catalog and job catalog:
IJ SYSCT IJ SYSUC identifies the master catalog, both when you initially define
it (using AMSERV) and when you begin a terminal session. You should use the PERM option when you define it.
identifies a job catalog to be used for subsequent AMSERV jobs
or VSAM programs. Only one VSAM catalog is ever searched when a VSAM function is
performed. If a job catalog is defined, you may override it by using
the CAT option on the DLBL command for a data set. The following DLBL
command sequence illustrates the use of catalogs:
dlbl ijsysct c dsn mastcat (perm
identifies the master catalog, MASTCAT, for the terminal session.
dlbl ijsysuc d dsn mycat (perm
identifies the job (user) catalog, MYCAT, for the terminal session.
dlbl intestl e dsn test case (vsam
identifies a VSAM file to be used in a program. It is cataloged in the
job catalog, MYCAT. dlbl cat3 dsn testcat (cat ijsysct
identifies an additional user catalog, which has an entry in the master
catalog. Since a job catalog is in use, you must use the :AT option to
indicate that another catalog, in this case the master catalog, should
be used.
dlbl infile e dsn test input (cat cat3
identifies an input file cataloged in the user catalog TEST:AT, which
was identified with a ddname of CAT3 on the DLBL command.
The selection of a VSAM catalog for AMSERV jobs and VSAM programs
running in CMS is summarized in Figure 7.
If the DLBL command is issued with no operands, the current DLBL
definitions are displayed at your terminal:
ddnamel devicel (fnl ftl fml [datasetnamel]]
ddnamen devicen (fnn ftn fmn (datasetnamen]] DMSDLB220R ENTER DATA SET NAME: This message is displayed when you use the DSN? form of the DLBL
command. Enter the exact DOS or as data set name. DMSDLB320I NUMBER OF DISK ENTRIES RECORDED This message indicates that nine volumes have been specified for a data set, which is the maximum allowed under CMS. 70 IBM VM/370 CMS Command and Macro Reference
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