Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp
Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!decwrl!sun!guy
From: guy@sun.uucp (Guy Harris)
Newsgroups: net.unix
Subject: Re: memory management primitives availability in 4.2BSD
Message-ID: <2115@sun.uucp>
Date: Thu, 11-Apr-85 02:11:11 EST
Article-I.D.: sun.2115
Posted: Thu Apr 11 02:11:11 1985
Date-Received: Sat, 13-Apr-85 04:49:26 EST
References: <9823@brl-tgr.ARPA> <9836@brl-tgr.ARPA>
Organization: Sun Microsystems, Inc.
Lines: 16

> The proposed 4.2BSD memory management syscalls were not provided
> with 4.2BSD.  Word was that the code had been written but failed
> on VAX-11/750s due to problems with the firmware.  Supposedly the
> latest DEC ECO was supposed to fix that, so a future release of
> 4.nBSD can include this facility.

If the 4.2BSD code used copy-on-write, this is possible; supposedly,
if the 750 took a protection fault due to lack of write permission,
the instruction could not be restarted (I believe some of the information
used to restart was scrambled) so that you couldn't do copy-on-write.
I believe System V Release 2 Version 2 uses copy-on-write, so either
1) it's not really a problem, 2) there's a work-around, or 3) S5R2V2
requires the latest ECO.

	Guy Harris
	sun!guy