Xref: utzoo comp.os.misc:527 comp.os.cpm:1798
Path: utzoo!attcan!uunet!bywater!acheron!clarke
From: clarke@acheron.UUCP (Ed Clarke)
Newsgroups: comp.os.misc,comp.os.cpm
Subject: Re: a very naive Question???
Message-ID: <251@acheron.UUCP>
Date: 10 Oct 88 03:11:15 GMT
References: <6693@ut-emx.UUCP>
Lines: 25

From article <6693@ut-emx.UUCP>, by kannan@ut-emx.UUCP (Natarajan Shanmugh):
> Followup-To: 
> Distribution: 
> Organization: UTexas Computation Center, Austin, Texas
> Keywords: Virtual Memory
>     I read an article in UNIX World comparing system V and AIX. It clearly stated that System V did not have VM(Virtual Memory concept). Can someone clear the following doubts for me through e-mail to nataraj@happy.cc.utexas.edu
>    (1) If there is no VM, how does the operating system, bring the programs from secondary storage to main for execution.(System V )
>    (2) How does MS-Dos solve the above problem?
>    (3) I have comments like Unix needs at least 4M of main memory?

1. That's Virtual Machine not Virtual Memory.  AIX uses VRM which is a sort
of low level idealized machine that comes between AIX and the true hardware.
It complicates life quite a bit when you want to add support for non
standard devices.  I think it's supposed to disapear in the future.

2. MS-Dos has neither.  It's a program loader that runs in 8086/8088
mode (< 1 Meg).  Yeah, it'll run on 80286/80386 machines, but it doesn't
take advantage of any of the extended features.

3.) Unix always needs one more meg than you have installed, either main
memory or secondary storage but usually both. ;-)

-- 
Ed Clarke
uunet!bywater!acheron!clarke