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

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