Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!uunet!seismo!dimacs.rutgers.edu!mips!public!valentin
From: valentin@public.BTR.COM (Valentin Pepelea)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Virtual Memory Program?
Message-ID: <1999@public.BTR.COM>
Date: 3 Mar 91 05:45:24 GMT
Organization: BTR Communications, Mtn. View, CA
Lines: 30

In article peter@cutmcvax.cs.curtin.edu.au (Peter Wemm) writes:
>
> Wow!  Any chance that something might come of it?  Are you able to distribute
> it? Or even sell it? (Or has somebody else got the rights to it??)

Before you jump up and down with joy, let me first tell you that virtual memory
can not be automatically used by applications out there. Virtual memory may be
allocated only to programs which explicitly request it. Therefore the
usefullnes of the VM handler is cut down by an order of magnitude.

The problem is that current applications expect physical memory, and often
access their memory whithin a Forbid(). That is a no-no for virtual memory,
since multitasking has to be re-enabled upon a page fault. Since there is
no way to find out why a Forbid() occurred, there is no way for the VM handler
to safely re-enable multitasking.

> You can't expect to dangle a carrot like that and not expect a bite!!! :-)

In order to distribute virtual memory, I would first like to polish it up,
by giving it a little window in which to plot the paging frequency and other
goodies like that. But I have no inclination to give up my free time or one
of my other projects to do that. On the other hand, if someone dangled a carrot
in front of my nose...

Valentin
-- 
"An operating system without virtual memory      Name:      Valentin Pepelea
 is an operating system without virtue."         Phone:     (408) 985-1700
                                                 Usenet:    mips!btr!valentin
                     - Ancient Inca Proverb      Internet:  valentin@btr.com