IBM System/370 145 Manual page 171

The preprocessor produces as output spanned variable-length (OS VS or
Vas) format data that can be writt:en on seven- or nine-track tape or on
direct access storage. Input records longer than 32,755 bytes are
reblocked, since OS BSAM cannot handle a physical data block longer than
3 2K. VS or VBS format tape can· bE~ unlabeled or have OS standard labels,
in addition to any 1400/7010 label.s. The preprocessor converts
1400/7010 labels and tapemarks int:o data records that are recognized by
the emulator program. Thus, if VS or VBS format tapes with 1400/7010
label data records are to be procE~ssed by System/370 programs, the tape
must be rewritten to relJlove the label data records or the System/370
program must contain a routine to recognize these records.
The T'ape Postprocessor operates in a program area of 5K bytes plus
I/O buffer requirements and
perfol~ms
the reverse of the Tape
Preprocessor. The. postprocessor program is useful when a copy of a data
set in OS VS or VBS and another
in
1400/7010 format are required or if
mixed density 1400/7'010-format fil.es are required. (The 1400/7010-
series emulator programs accept as; input and produce as output both the
formats handled by these two tape formatting programs.)
The tape formatting and emulator programs handle 200-, 556-, 800-,
and 1600-BPI density, mixed-densit:y, and even-,. odd-, and mixed-parity
seven-track tapes.. VS, VBS, or 1~~00/7010-format data written on nine-
track tape is coded in EBCDIC. If VS or VBS format tapes are processed
on a seven-track tape unit, the tape control unit must have seven-track
and data convert features installE!d. The alternate mode used by stand-
alone system/360 1400/7010 emulators is accepted by the Model 145
emulator programs as well.
While eXisting tape files with blocks longer than 32K bytes must be
preprocessed, conversion to VS or VBS format offers the following
advantages:
• The ability to emulate tape dalta sets on direct access devices for
more flexibility in I/O devicE! assignment
• The ability to increase emu.lat.or job performance by reblocking
1400/7010-series-format tape f:iles with short blocks
• The aqility to reduce processor storage buffer requirements by
reblocking files with very l.az-ge blocks
• The ability to process VS or ~~S format tape and move mode disk data
sets with both OS and emulateol 1400/1010-series programs if the OS
programs can handle 1400/1010 label and tapemark records. (Load
mode disk data sets are not ac:cepted by OS programs.)
The disk formatting program supplied operates as a processing
program, and an area of 2K bytes i.n addition to buffer requirements is
needed for its execution. This pz:'ogram must be used to format
System/370 disk volumes that are t~o contain 1400/7010 disk data. In
order to convert 1400/7010 disk fi.les that are being processed on a
1400/7010 system or by a stand-alone System/360 1400/7010 emulator to a
format acceptable to the Model 145i emulator program, the following must
be done:
1 • The contents of the disk mUlst be dumped to tape, using a
1400/7010 disk-to-tape utility program. This must be done on a
1400/7010 system if the data was created and is being processed
on a 1400/7010 system. A System/360 with a stand-alone 1400/7010
emulator must be used to convert 1400/7010-format data files that
are being emulated on Syste~m/ 360 direct access devices.
A Guide to the IBM System/370 Mode!l 145
161