Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!decwrl!ucbvax!CS.PURDUE.EDU!jng
From: jng@CS.PURDUE.EDU
Newsgroups: comp.os.xinu
Subject: Re: Virtual memory?
Message-ID: <8904072243.AA13075@gwen.cs.purdue.edu>
Date: 7 Apr 89 22:43:14 GMT
References: <41516@tut.cis.ohio-state.edu>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 38


>>Is the third book (volume III) out?
>>I am interested in:
>>	1) Modifying Xinu so that a program can be loaded and run
>>	   from disk.
>>	2) Looking at protected memory / virtual memory additions.
>>The second book mentions Virtual memory will be in Vol III


A prototype of the Virtual Memory Xinu (VM Xinu) operating system is
currently being built.  VM Xinu is a hierarchical virtual memory operating
system with features such as multiple threads of control within an address
space, kernel processes, shared/protected memory, paging to a remote
machine, and dynamically loaded processes.

VM Xinu is currently running on both Digital UVAX I's and SUN3/50's
(LSI11/23's do not have virtual memory support).  The page server runs on a
VAX11/780 as a user level process under 4.3BSD Unix  (we have also run it
on a SUN3/50 under SunOS).   The page server is able to server both
architectures (UVAX I and SUN3/50) simultaneously.  The UVAX I version is
slightly more advanced since it has dynamically loaded processes which run
in user/kernel mode.  We are in the process of adding user/kernel mode and
dynamically loaded processes to the SUN version.

As Dr. Comer indicated in his last posting, VM Xinu is still a prototype
and is *not* ready for general distribution.  I will be posting a more
detailed description of the design and implementation of VM Xinu in the
near future.  If you are extremely interested in looking at it (and you're
are a Xinu guru and like a challange) or if you have any
questions, feel free to contact me (jng@cs.purdue.edu).

Jim Griffioen
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