Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!umd5!decuac!felix!zemon
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.ultrix
Subject: Re: /etc/init -> /bin/init
Message-ID: <33326@felix.UUCP>
Date: 3 May 88 23:07:53 GMT
References: <31098@felix.UUCP> <32290@felix.UUCP>
Sender: zemon@felix.UUCP
Reply-To: chris@mimsy.UUCP (Chris Torek)
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 27
Approved: zemon@felix.UUCP
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>>From article <31098@felix.UUCP>, by dhesi@bsu-cs.UUCP (Rahul Dhesi):
><This solves all upgrade problems.  All who can get a source license
><should try this [running 4.3 BSD instead of Ultrix].

In article <32290@felix.UUCP> bin@rhesus.primate.wisc.edu
(Brain in Neutral) writes:
>Doesn't work too well for VAXBI systems, though, unless someone's figured
>how how to hack BSD to understand the BI bus.  Anyone?

Not too difficult.  The problem is that only the 8[23][05]0 are simple
BI machines.  The more interesting machines---the 8700, 8800, and the
recently-released whatever-they-are-called---have an internal CPU/
memory bus and get at BI buses via adapters.

Making 4.3BSD run on the 8250 was relatively easy, since all I had to
do was lie about the bus structure (and claim the KDB50 adapter was
on the Unibus!).  Even doing an 8800 with two BIs would be possible,
since the 86x0 can have two SBIAs and has IOA maps.  Still, the whole
autoconfiguration system needs to be rewritten with the new hardware
in mind.

Debugging my KDB50 adapter code was harder....  (Did you know the
VM code assumes that the pageout driver has copied the PTEs, and that
it is safe to smash them?  Oops!  I found out with a `host buffer
memory access error'.)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris@mimsy.umd.edu	Path:	uunet!mimsy!chris