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From: tencati@JPL-VLSI.ARPA
Newsgroups: mod.computers.vax
Subject: VMS/SYSGEN: VIRTUALPAGECNT Parameter
Message-ID: <870113140054.051@Jpl-VLSI.ARPA>
Date: Tue, 13-Jan-87 17:00:53 EST
Article-I.D.: Jpl-VLSI.870113140054.051
Posted: Tue Jan 13 17:00:53 1987
Date-Received: Thu, 15-Jan-87 03:04:43 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 27
Approved: info-vax@sri-kl.arpa


A system manager on another system here at JPL asked me to forward the
following question to the list:

Can the VIRTUALPAGECNT parameter in SYSGEN be set to something larger
than the 300,000 page limit specified as the "Maximum", and if so, 
what are the possible ramifications of such a move?

He says he is using the page file as a buffer for loading in a data stream
from an AMPEX tape drive into an array in an application program. He says
there are no bus-contention problems, but it appears the application
program aborts due to the vax not being able to read the data in fast enough.
The application is written in fortran, but the tape I/O routine is in Macro.
The vax is being used by a single user with a 400,000 page file quota and a
400,000 block page file.  The data is read into a 280,000 byte buffer using
3 QIOs.

The process runs with a wsextent of 5100 pages, and as soon as the process 
exceeds (hits) this limit, the process bombs.  

Aside from programming style, is there anything in VMS that could be modified
to help these folks with their problem?

Thanks,

Ron Tencati
System Mgr, JPL-VLSI.ARPA