Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ukma!husc6!bu-cs!madd
From: madd@bu-cs.BU.EDU (Jim Frost)
Newsgroups: comp.sys.ibm.pc
Subject: Re: virtual memory question
Message-ID: <31088@bu-cs.BU.EDU>
Date: 13 May 89 17:07:26 GMT
References: <27562@teknowledge-vaxc.ARPA>
Reply-To: madd@bu-it.bu.edu (Jim Frost)
Followup-To: comp.sys.ibm.pc
Distribution: usa
Organization: Software Tool & Die
Lines: 39

In article <27562@teknowledge-vaxc.ARPA> crodrigu@teknowledge-vaxc.ARPA (Cliff Rodriguez) writes:
|I am looking for a way to use my hard disk for virtual memory.
|Which operating systems for the pc support this?
|Does it require a 386.     

There are a variety of them.  Which is for you depends on what you
want to do.

Xenix can give you that on an 80286 or 80386 box, although I believe
that there are allocation limitations on the 80286 version.  Several
other manufacturers' versions of UNIX System V run on 80386 boxes.
Personally I recommend Interactive 386/ix although the 80386 version
of Xenix is very usable.  Sun has the 386i running their version of
BSD UNIX -- a real performer but at high cost.  All of the 80386
versions of UNIX provide true VM.

If you require the MS-DOS environment, you will be limited to 640k of
memory per application (ignoring EMS) although there are many programs
which allow you to use many of these environments.  Desqview and
Windows are two examples.  I recommend avoiding Windows on an 80286
machine, but both are fairly usable on an 80386 machine.  On the 80386
there are several systems which take advantage of the virtual 8086
mode to provide many small MS-DOS environments; 386-to-the-max is one
such program.

Lastly there is OS/2 which has some VM support (I say "some" because
it is not possible to get very large "contiguous" areas of memory; if
this is not a problem then OS/2 has VM so far as you are concerned).
Due to the decision to implement OS/2 on the 80286, the virtual memory
manager has to bend over backwards to provide VM, and performance
drops dramatically as soon as VM is actually used.  For this reason I
recommend avoiding OS/2 if you need VM (and for many other unrelated
reasons).

If you really want to make use of VM, UNIX on an 80386 is probably
your best choice.

jim frost
madd@bu-it.bu.edu