In message <000f01cb22b5$45d4f3c0$d17edb40$@com>, Mark Ranft 
<[log in to unmask]> writing at 13:00:25 in his/her local time opines:-
>I wonder which is more of a concern:
>-  An unexplained Data PAGE Fault or

Unexplained doesn't mean inexplicable.

Conjecture a dataset at the very end of your data division.

Somebody added extra fields to it.

Nobody told your COBOL program; though they might have told the copy 
library.

You run your program. Image tries to give you the record. It is not 
aware you think it smaller than it is. But MPE is, and the attempt to 
encroach outside the designated area produces the smart rebuke you saw.

You recompile. You pick up the new, expanded, dataset definition from 
the copy library. Enough data space is duly reserved..

All thereafter is sweetness and light.

>-  wondering if the source code that you had been running matches the object.

If you embark upon a migration project, where your emulated code is 
required to match the original MPE code, *demand* that the source you 
are given to migrate is compiled on MPE to produce the reference system.

By all means allow the client to provide a copy of their production 
system for further comparison; if the source they provide you is not the 
source of the code they are running, this is the only way you (and they) 
will find this out.

But the A-B-C comparison is essential to isolate the results of 
incorrect emulation from those of incorrect source/data/what-have-you 
provision.

>If simply re-compiling the code did indeed solve the issue, either the 
>compiler had changed to fix a bug that you only ran into recently, or 
>the compiler/link options had changed, or the source code and object 
>didn't match.

Or (as above) there were copy libraries involved that had changed, 
and/or COBOL's inability to achieve as a matter of course what 'make' 
achieves for C.....

>Mark Ranft
>Pro 3K
>
>-----Original Message-----
>From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On 
>Behalf Of Dave Vorgang
>Sent: Tuesday, July 13, 2010 12:19 PM
>To: [log in to unmask]
>Subject: [HP3000-L] Internal Trap
>
>I recompiled my program and the error went away.
>
>Thank you,
>
>Dave

-- 
Roy Brown        'Have nothing in your houses that you do not know to be
Kelmscott Ltd     useful, or believe to be beautiful'  William Morris

* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *