The following is a list of some of the things a recovery routine
should do if the recovery is to be effective.
The items are arranged in a way that suggests the order in which
you might do them; however, you must decide yourself the order that
would work best for your particular routine.
- Preserve the return address to the system.
- Check for the presence of an SDWA (for ESTAE-type recovery routines
only).
- Establish addressability to the parameter area passed by the mainline
routine. How you do that depends on whether an SDWA is present.
- Check the contents of important fields in the SDWA.
- Determine the location of the parameter area.
- Determine why the routine was entered.
- Determine if this is the first recovery routine to get control.
- Check the contents of the parameter area passed by the mainline.
- Determine if this is a repeated error (to avoid recursion).
- Determine when and where the error occurred.
- Provide information to help determine the cause of the error:
- Save serviceability data in the SDWA.
- Request recording in the logrec data set.
- Request a dump of storage.
- Try to correct or minimize the effects of the error.
- Determine whether the recovery routine can retry, decide whether
to retry or percolate, and take the appropriate actions (such as cleaning
up resources).