Path: utzoo!attcan!uunet!husc6!bloom-beacon!oberon!sdcrdcf!csun!polyslo!dorourke
From: dorourke@polyslo.UUCP (David O'Rourke)
Newsgroups: comp.sys.mac
Subject: Re: FullWrite Professional
Message-ID: <2891@polyslo.UUCP>
Date: 26 May 88 03:04:33 GMT
References: <8805172016.AA09499@decwrl.dec.com> <2730@polyslo.UUCP> <4849@ihlpf.ATT.COM>
Reply-To: dorourke@polyslo.UUCP (David O'Rourke)
Organization: Cal Poly State University -- San Luis Obispo
Lines: 30

In article <4849@ihlpf.ATT.COM> straka@ihlpf.UUCP (55223-Straka,R.J.) writes:
>What ever happenned to the concept of demand paging (virtual memory) or
>segmented code (non-virtual memory)? 

   Nothing, but Until the macintosh II and the 68851 most personal computers
haven't had any sort of virtual memory like you're used to on a Larger System.

   The programmer has to make an effort to swap out segments of code and Data.
The Macintosh does allow segmentation of code segment, and resources do allow
limited swapping of data structures. the programmer has to be aware of
what's going on and can't quite program blindly like you can on a true VM
system.

   In answer to your question about the system file things are read in based on
demand, and aren't typically preloaded.  So where computer software says it
need's 1 meg of memory it normally because the software needs that much data
space which it harder to swap than code on the Macintosh.

   Flame retardant:  I know VM isn't this simply and the Macintosh does offer
a primative form of VM.  But I don't think it's the same as what the original
poster meant.  If anyone feels my explanation isn't sufficent I'll be happy to
cover the gory details for them via e-mail.  But I don't this the net really
wants to know.  But if they do I'll do my best to answer, and I would appreciate
any help any informed netlanders have to offer.


-- 
David M. O'Rourke

Disclaimer: I don't represent the school.  All opinions are mine!