Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-XX8 You can also use the MOVEFILE command to display tape labels on your
terminal if you want to see what these labels leok like. The following sequence displays the VOLl and first RDRl labels on tap4 if the tape has
standard labels:
filedef in tap4
filedef out term
tape rev (tap4
move in out
LABELDEF COMMAND The LABELDEF command is used to specify the exact data you want written
in certain fields of a HDR1 or EOFl tape label for output. It can also
be used to specify fields in the same labels that you want checked en
input. If you do not explicitly specify a field for output, a default
value is used. If you do not explicitly specify a field for input, the
field is not checked. For example:
labeldef abc fid master volseq 1 exdte 77364
used for input tells CMS to check the file identifier volume sequence
nu.ber and expiration date in an input BDRl label. No other fields in
the label are checked. The same specification used for output causes
the BDRl label to have MASTER written in the file identifier field, 1
written in the volume sequence number field and 77364 written in the
expiration date field. Default values are written in the RDRl fields
that are not specified.
Default values for HDRl labels are as follows:
FID VOLID VOLSEQ FSEQ GENN GENV CRDTE EXDTE SEC for OS simulation, the DDNAME (Specified on FILEDEF)
for CMS/DOS, the DTFMT symbolic name
fer CMS TAPESL macro, the LABELDEF id (LABID=labeldefid)
parameter CMSOOl 0001 0001 blanks
blanks
current date that label is written
current date that label is written
o
The filename on the LABELDEF command is used to connect your label
definition to a file defined elsewhere. This is why you specify
different data for file name depending on the type of tape label
processing you are doing. Filename is DDNAME for OS simulation, symbolic name for CMS/DOS and labeldefid for TAPESL. I The LABELDEF command takes the place of the DOS/VSE TLBL statement
for eMS/DOS. 122.12 IBM VM/370 eMS User's Guide

Pg. of GC20-1819-2 Rev March 30, 1979 by Supp. SD23-9024-1 for 5748-XX8 END-OF-VOLUME AND END-OF-TAPE PROCESSING There is no true end-of-volume support available with CMS tape label
processing. FEOI instructions are not supported under as simulation and
there is no automatic volume switching. Multivolume files are not
supported. The follcwing features exist to aid the IBM standard label
tape user when he reaches end-of-tape on output or an EOV label in
input. These are the only ways in which CMS supports EOV processing. • Input - When a CLOSE macro is issued or when a TAPESL macro processes
an input trailer label, a message is issued if the label read is an EOV1 label instead of an EOF1 label. The EOVl label is then
processed exactly as if it were an EOF1 label. You must request that
the operator mount a new tape and reopen a file if you want to
continue processing the data. • Output - Under eMS/DOS and OS simulation processing only (that is,
the processing does not occur for TAPESL or CMS commands), the
following limited EOV processing occurs:
a. If you specify that you have an IBM standard label tape file, a
single tape mark is written to end your data. This occurs when
end-of-tape is sensed on output while you are using regular access
method macros to write the file. The tape mark is written
immediately after the record that caused the EOT to be sensed.
Following this tape mark, CMS writes an EOV1 label and a single tape
mark. It then rewinds and unloads your tape. A message is issued
telling you that an EOV1 label was written. If you specified
nonstandard labels instead of writing the EOV1 label, an exit to the
nonstandard label routine you specified for the file is taken after
the end-of-data tape mark is written. For BLP or NL files, only the
ending tape mark is written.
b. CMS/DOS jobs are always canceled after an EOT condition is
detected on output. In order to continue processing the tape, you
must have a new tape mounted, run the same job over again or run a
new job and reopen the file.
c. Os simulation programs that use QSAM or contain a BSAM CHECK macro cause an abend when EOT is detected, with code 001 after an
error message. A BSAM program that does not use a CHECK macro has no
way of detecting the EOT condition. Such a program continues to try
to write on the tape after it is rewound and unloaded. The program
enters a wait state rather than continue running to a normal or
abnormal completion. Therefore, you should always include a BSAM CHECK macro after the WRITE if you expect your program to reach
end-of-tape. OS simulation users are also responsible for completing
processing on a new tape with the same or a new job after an EOT is
detected.
d. If you are a CMS/DOS user you always get the automatic output
end-of-tape processing described above. However, if you are an as simulation user and do not want CMS to do any special end-of-tape
processing, you can suppress it by using the NOEOV option on your
FILEDEF command for the file. If you enter:
filedef dd1 tap3 sl (noeov
no tape .arks or EOV1 labels are written when EOT is sensed on
output. Your tape is not rewound and unloaded. However, the progra.
causes an abend if you use QSAM or include a BSAM CHECK macro after
your WRITE macro. Without a CHECK macro, a BSAM program runs the
tape off the reel when EOT is sensed and NOEOV is specified. Section 7. Using Real Printers, Punches, Readers, and Tapes 122.13