AS/400 job recovery

[lgoodbar@xxxxxxxxxxxxxxx (lg - Loyd Goodbar)]

I was wondering... the AS/400 offers so much as far as system security,
integrity, etc. is concerned. Thinking about that, I was wondering why the 400
doesn't offer any form of job recovery.

When a job is running, the 400 has to be able to page the entire job out of
memory if necessary. This predicates that state information for CPU processing
as well as IO processing (file RRNs, record of input, output) can be saved and
restored as necessary.

However, when a shutdown is performed, all job information is lost. (I'm
considering user jobs here; system jobs are restarted via the startup
program.)

What I was thinking was: when a PWRDWNSYS or ENDSBS was performed, could
active job information be saved, and optionally restored and resumed when the
system/subsystem was restarted?

For instance, if I powered down the system with 5 jobs active in QBATCH, when
I restarted the system, the system operator (or secofr, whoever) could be
presented with a screen of previously active jobs: (example)

These jobs are not currently active, but were active when the subsystem was
ended. The sysopr could choose 1 to resume the job where it left off; 2 to
resubmit the job from the beginning; 4 delete the job; 5 display job
attributes (WRKACTJOB opt 5)
---------------
Resume user jobs

Options:
1=Resume 2=Submit 4=Delete 5=Display

SUBSYS/JOB Date/Time Started Date/Time Suspended
MIS
_ CRTBNDRPG/GOODBAR/300010 11/06/98 17:53:00 11/06/98 17:54:08
QBATCH
_ QBATCH/GOODBAR/300001 11/06/98 14:03:34 11/06/98 17:54:03
_ MONITOR/QSYSOPR/300002 11/04/98 01:00:00 11/06/98 17:54:04

F3=Exit F11=View 2 F12=Cancel F23=Delete all F24=More keys
... other options??
---------------

Obviously, the sysopr must know what the job did; it wouldn't help if s/he
restarted a job that consumed all system resources or whatever.

The only major problems with this I could think about would be if access paths
were rebuilt during an IPL or changed between the time a job was "suspended"
and when it resumed. Would journaling be required on all files used by a job
to have it resumable? What other wierd things am I missing that explain why
this feature couldn't be present in OS/400?

Just some thoughts,
Loyd Goodbar
--  
"You can nail me, but not to a tree."
lgoodbar@watervalley.net  ICQ#504581  http://www.watervalley.net/users/lgoodbar/
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