When you write a recovery routine, you must take into consideration
a number of environmental factors that are present when the recovery
routine gets control, and that are present when a retry routine gets
control. This information discusses environmental factors in two broad
categories, distinguishing register contents from all other environmental
factors:
- Register contents.
Recovery routines
are interested in register contents at the following times:
- All other environmental factors.
The
other environmental factors important in a recovery environment are:
- Authorization: problem state or supervisor state, PSW key, and
PSW key mask (PKM)
- SDWA storage key
- Dispatchable unit mode
- Cross memory mode
- AMODE
- ASC mode
- Interrupt status
- Dispatchable unit access list (DU-AL)
- Locks
- Program mask
- Condition of the linkage stack
- Authorization index (AX)
- Extended authorization index (EAX)
This information discusses each of the environmental factors, and
makes distinctions, where necessary, that depend on the following:
- Whether the system provided an SDWA
- Whether you have an ESTAE-type recovery routine or an FRR
- Whether you are dealing with the recovery routine or the retry
routine.