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Notes:
1. The codes are as follows:
┌──────┬────────────────────────────────────────────────────────────┐
│ VSE │ MVS (BSAM only) │
├──────┼────────────────────────────────────────────────────────────┤
│ REW │ No equivalen─. The op─ion specified in ─he DISP │
│ RUN │ parame─er of ─he DD s─a─emen─ is ─aken. Refer │
│ │ also ─o ─he OPEN/CLOSE op─ions. │
│ BSR │ BSR, number of blocks │
│ FSR │ FSR, number of blocks │
│ BSF │ BSM Bo─h of ─hese codes cause spacing pas─ ─apemark, │
│ FSF │ FSM ─hen, spacing in ─he opposi─e direc─ion over ─apemark.│
│ WTM │ No equivalen─ │
│ ERG │ │
│ BSL │ No equivalen─ │
│ FSL │ │
└──────┴────────────────────────────────────────────────────────────┘
2. Under MVS, if the forward or backspace operation does not complete
successfully, control is passed to the error analysis routine (SYSAD). If you
do not specify a SYNAD routine, the task terminates abnormally.
3. If a tapemark is encountered for DSR or FSR, control is returned to the
processing program, and register 15 contains a count of the uncompleted
forward spaces or backspaces. If the operation completes normally, register
15 contains zero.
4. If you specify OPTCD=H in the data control block, the CNTRL macro
instruction can perform record positioning on VSE tapes that contain
embedded checkpoint records. Imbedded checkpoint records encountered
during the record positioning are bypassed and are not counted as blocks
spaced over. You must also specify OPTCD=H in a JCL DD statement. The
CNTRL macro instruction cannot be used to backspace VSE 7-track tapes
that are written in data convert mode that contain embedded checkpoint
records (BSAM).
NOTE Macro
The result of the NOTE macro is the same in VSE and MVS. Information is
returned in register 1 in the format 0bbb. If you use NOTE under MVS, the tape
on which the data set resides must have standard labels if the OPEN option
RDBACK or DISP=MOD has been specified. The MVS NOTE macro is valid only
for BSAM and BPAM.
POINTW / POINTR Macros
VSE NOTE filename
(1)
MVS NOTE dcbaddress
(1-12)
VSE POINTW
POINTR
filename
(1)
MVS POINT dcbaddress , blockaddress
(1-12) (2-12)
(0)
Chapter 13. Assembler 299