gtpi1m0pSystem Installation Support Reference

Catastrophic Recovery

User exit routine UCCCAT is invoked from catastrophic recovery processing after the tape queues have been cleared, but before tapemarks are written to the real-time tapes. Exit point CAT is in CSECT CCCPSF.

UCCCAT is provided to give users the opportunity to log critical records to tape. UCCCAT is invoked once for every active real-time tape found in the real-time tape chain. UCCCAT should first examine the tape status table entry to see if it is a tape for which user exit processing is required. If it is, UCCCAT should invoke CEDTWBK, in the CSECT CCCPSE, to write additional blocks to tape.

Note:
Save your registers and change them as needed before you call CEDTWBK from the UCCCAT user exit.

Routine CEDTWBK expects the following conditions at entry:

R0
The length of the record to be written. Length must not exceed 32 690 bytes.

R1
The main I-stream system virtual address of the record to be written.

R2
Module number of the tape being written to (supplied by CCCPSF on entry to the user exit).

General Conditions at Entry

The registers at entry to UCCCAT are:

R0
Module number of the tape being processed. At the conclusion of user exit processing, CCCPSF will send the dummy record/tapemark sequence to the referenced tape device.

R6
Tape status table section 1 entry for the tape being processed. This register can be used to determine whether the tape name in the tape status table entry identifies a tape that requires user processing. See the ITSTB DSECT.

R11-R15
See User Exit Routines - Common Entry Conditions.

Refer to a listing of CCCPSF for the contents of the remaining registers.

System Conditions at Entry

System state
Supervisor, normal I/O suspended

System mask
Masked

Protect key
0

Address space
SVM on the main I-stream.

Programming Considerations at Entry

  1. User processing must not change the system state. Return must be made to the next sequential instruction.
  2. See User Exit Routines - Common Programming Considerations for other considerations.

Programming Considerations on Return

See User Exit Routines - Common Return Conditions.

General Conditions on Return

See User Exit Routines - Common Return Conditions.