CLEAR
DLBL
removes any existing definitions for the specified ddname.
Clearing a ddname before defining it ensures that a file
definition does not exist and that any options previously
defined with that ddname no longer have any effect. fn ft indicates that this is a and the file identifier (fn
ft) that follows is a CMS filename and filetype.
FILE ddname is the default CMS file identifier associated with
all non-CMS data sets. (See Usage Note 3 for CMS/DOS users.) DSN indicates that this is a non-CMS file.
? indicates that you are going to enter the data set name
interactively. When prompted, you enter the data set name or
fileid in its exact form, including embedjed blanks, hyphens,
or periods. quaIl [quaI2 •.• qualn] Sy Sxx: x
PERM
is an as data set name or DOS file-ide Only data sets named
according to standard as conventions may be entered this way; you must omit the periods between qualifiers. (See Usa.ge Note
2. ) (CMS/DOS only.) indicates the system or programmer logical
unit that is associated with the disk on which the disk
file resides. The logical unit must have been previously
assigned with the ASSGN command. If a DLBL definition is
already in effect for the specified ddname, SYSxxx may be
omitted; otherwise, it is required.
indicates that this DLBL definition can be cleared only
with an explicit CLEAR request. It will not be cleared
when the DLBL * CLEAR command line is entered.
All DLBL definitions, including those entered with the PERM option, are cleared as a result of a program abend or HI
(halt execution) Immediate command. indicates that any existing DLBL for this ddname is not to
be but that conflicting options are to be
overridden and new options merged into the old definition.
Both the ddname and the file identifier must be the same in
order for the definitions to be merged. NOCHANGE does not alter any existing DLBL definition for the
specified ddname, but creates a definition if none existed. VSAM indicates that the file is a VSAM data set. This option
must be specified for VSAM functions unless the EXTENT, MULT, CAT, or BUFSP options are entered or the ddnames IJSYSCT or IJSYSUC are used. EXTENT indicates that you are going to use access method services
to define a VSAM catalog, data space, or unique cluster and
you want to enter extent information. MULT indicates that you are going to reference an existing
multivolume data set and you want to enter the volume
specifica tions. Section 2. CMS Commands 61

DLBL catdd identifies the VSAM catalog (defined by a previous DLBL
definition) which contains the entry for this data set. You must use the CAT option when the data set you are
creating or identifying is not cataloged in the current job
catalog. catdd is the ddname in the DLBL definition for
the catalog. BUFSP nnnnnn
specifies the number of bytes (in decimal) to be I/O buffers by VSAM data management during
execution, overriding the BUFSP value in the ACB file. The maximum value for nnnnnn is 999999;
commas are not permitted.
used for
program
for the
embedded
1. To display all of the disk file definitions in effect, enter:
dlbl
The response will be:
ddname DISK fn ft
If no DLBL definitions are in effect, the following message is
displayed: DMSDLB3241 NO USER DEFINED DLBL'S IN EFFECT
2. To enter an OS or DOS file identification on the DLBL command line,
it must consist of 1-to 8-character qualifiers separated by
periods, with a maximum length of 44 characters, including periods. For example, the file TEST.INPUT.SOURCE.D could be identified as
follows:
dlbl ddl c dsn test input source d (options ••• Or, it may be entered interactively, as follows:
dlbl ddl c dsn ? (options DMSDLB220R ENTER DATA SET NAME:
test.input.source.d
Note that when the data set name is entered interactively, the data
set name must be entered in its exact form; when entered on the
DLBL command line, the periods must be omitted. You must use the interactive form to enter a DOS file-id that
contains embedded blanks or hyphens.
3. In DJS/VS, a data set that has been defined as is opened
with an error code of X· 11'. CMS supports the DUMMY operand of the
DLBL command in the same manner. OS users should not use the DUMMY operand in CMS, since a dummy data set does not return, on open, an
end-of-file indication.
62 IBM VM/370 CMS Command and Macro Reference