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From: jwp@larry.UUCP
Newsgroups: comp.unix.wizards
Subject: MVAXII booting:  raboot.s question
Message-ID: <295@larry.UUCP>
Date: Tue, 11-Aug-87 16:10:30 EDT
Article-I.D.: larry.295
Posted: Tue Aug 11 16:10:30 1987
Date-Received: Thu, 13-Aug-87 01:25:40 EDT
Organization: University of Wisconsin Space Astronomy Lab, Madison, Wisconsin
Lines: 32
Keywords: raboot bootra MicroVAX II

We have several MicroVAX IIs:  one running 4.3BSD and
another running ULTRIX 32M.  My question concerns the
raboot.s source is /usr/sys/mdec.  The raboot.s distributed
with 4.3BSD produces a boot block that appears not to work
with our rd53.  We get a "halt instruction encountered"
when we try to reboot.  We compared the first block
from /dev/ra0a on the BSD machine with the corresponding
block from the ULTRIX machine, and they miscompare.

A disassembly of the ULTRIX boot block starts off with
	nop
	nop
	brb	5
	halt
	halt
	nop

A disassembly of the BSD boot block generated from raboot.s starts with
	halt
	halt
	nop
	nop
	nop
	nop

My questions:
1.  why doesn't raboot.s assemble to something useable?
2.  where does ULTRIX get its boot block, and why is it different
    than the BSD block?
-- 
----
Jeff Percival (jwp@larry.sal.wisc.edu)