Everhart,Glenn
From:	schenkenberg@eisner.decus.org
Sent:	Wednesday, April 08, 1998 9:11 AM
To:	Info-VAX@Mvb.Saic.Com
Subject:	Re: Question: checkpointed execution of programs
In article <6gfmq2$6g0$1@sunnews.cern.ch>, me@bad.domain.inet () writes:
> 
> I would like to know if there is an easy way in OpenVMS to get periodic
> checkpoints of an image execution saved in a file to get the execution
> restarted from the last checkpoint.  Any info about this? 
> Many thanks in advance, bye.
> 
> P.S.: Please anwer in the newsgroup, don't try to use the reply-to field.
> _____________________________________________________________

From some external activity or by some programmed, callable type routine
like a DO_CHECKPOINT?

I've recently enhanced my SHAPSHOT utility, in fact, I've completely re-
written the utility.  SHAPSHOT now allows any user (so privied) to force
a process running an image to create a process dump or (*new*) obtain the
call chain symbolic traceback (such as is output when an image dies with
an unhandled exception).  The original version relied upon an AST to be
delivered to the process.  This, of course, thwarted SNAPSHOT if the tar-
get process was executing in the context of an AST.  This *NEW* SNAPSHOT
does not have this problem!!!

The traceback used in the NEW SNAPSHOT is also callable.  I've toyed with
the idea of providing a callable "process dump" as well.  With some effort
a "restartability" feature could be added assuming all data manipulated in
the process is private.

So, in answer to your question:

> I would like to know if there is an easy way in OpenVMS to get periodic
> checkpoints of an image execution saved in a file

With my SNAPSHOT utility, the answer is yes.

> to get the execution
> restarted from the last checkpoint.

No, not yet.  But thanks for the suggestion...  ;)

--
VAXman-                                                     VAXman@TMESIS.COM
OpenVMS APE certification number: AAA-0001

... and in the end, the money you take is equal to the money you make.