Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!usc!jarthur!jmerrill
From: jmerrill@jarthur.Claremont.EDU (Confusion Reigns)
Newsgroups: comp.windows.ms
Subject: Re: DOS App Memory Usage (was: Win3.0 - More questions)
Message-ID: <7487@jarthur.Claremont.EDU>
Date: 15 Jun 90 06:43:00 GMT
References: <9906@rouge.usl.edu> <1990Jun12.140525.7945@cbnewsk.att.com> <1990Jun13.152605.14354@sj.ate.slb.com> <55227@microsoft.UUCP>
Organization: The Lords of the Known Universe, Inc.
Lines: 27

In article <55227@microsoft.UUCP> philba@microsoft.UUCP (Phil BARRETT) writes:
>In win 3.0 enhanced mode, a DOS application must be completely resident
>in order to run.  If the Virtual Machine does not have the background
>option set (via PIF editor or settings dialog), it will be swapped out
>to disk when it doesnt have the focus (ie, when its not foreground).  If
>you set the background option, you are telling windows that you want the
>application/vm to always be running and thus windows will never swap it 
>out.  So, if you have 2 such VMs, you will tie up over 1Mb in resident
>space.  Depending on your machine configuration and windows apps/device
>driver loaded you may not be able squeeze in another one.  Note that a
>lot of machines out there loose 384Kb of physical RAM to shadow ROM and
>thus are really 1.6Mb machines.  I wouldn't expect them to run more than
>2 background DOS apps at once.  Your milage may vary.

If this is true, why is there the "Lock application memory" option in the
PIF Editor?  My manual says, "While the application is running, if this
option is selected, Windows will keep the application in memory and not swap
it to the hard disk."  This sounds to me as though it swaps otherwise.

In a similar vein, a 2Mb computer at work with WfW and 4dos (640K) loaded at
the same time suffers from CONTINUOUS DISK ACCESS.  This goes on until I
kill the 4dos process; this, too, would seem to indicate that 4dos is
running in the background, but that it is being loaded again each time it
gets its timeslice, thus killing the computer.

--
Jason Merrill				jmerrill@jarthur.claremont.edu