ZiLOG Z80-RIO Operating System User's Manual page 173

6.17
SKIP BACKWARD
SKIP BACKWARD
Request vector:
Logical unit
Request code - 26 or 27
Data transfer area - ignored
Length - the number of records (not bytes) to be
skipped. On return, the number of records
skipped will be reported.
Completion return address
Error return address
Completion code
Supplemental parameter information - if the file is
open for random I/O, this field should contain
the address of a three-byte area where the
Action:
disk address of the record preceding the
current one will be reported. Otherwise, none.
The current record pointer is moved backward
through the file by the number of records
indicated. No data is transferred.
Possible errors:
All DISK ERRORs except PROTECTION (code C3)
are possible.
POINTER ERROR (code CA) - a pointer mismatch
occurred while traversing the records of the
file. The current record pointer is left
indicating the record following the error.
FILE NOT OPEN (code CB) - the logical unit
being accessed is not active. No action is
taken.
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