Rebooting 4.2BSD on a 780

[Chris Torek]

> From: andy at cheviot.UUCP (Andy Linton)
>
> Try looking at Section 6.1 in "Installing/Operating 4.2BSD"
> - Section 62 in Volume 2 of the system manual.
> It suggests that when at the console command level you can 
> say:-
> 	>>> B ANY

Yes, that happens to be wonderful and we use it all the time WHEN
WE ARE IN THE MACHINE ROOM.  What I was suggesting was a way to
boot from an alternate file while you're dialed in or logged in
from across campus, or across country, or whatever.

(Sorry about the shouting.)

By the way, some 750 boot ROMs have a bug that loses the flags
if you don't specify the device name, so we generally do

	B/3 DUA0

to come up single user from something other than ra(0,6)vmunix.
(Yes, our root file system on our 750s is on /dev/ra0g.)

You can also use B/2 to come up single user from /vmunix, or B/1
to come up multi-user from some other file.  For 780s, use B HPS
to come up single user from hp(0,0)vmunix, or type

	Halt
	Unjam
	Init
	LOad BOOT
	Deposit R10 0	! boot from hp (2=up, 3=hk, 9=ra, 10=ut, 11=rb, 14=rl)
	Deposit R11 1	! or D R11 2, which is what HPSBOO.CMD does
	STart 2

(The UPPercase stuff is the required parts of the full commands---or
at least the part I type; load might be abbreviable to "L"....)

At one point we were using R9 for the disk and partition numbers
so that we could boot off of hp(9,0)vmunix (MBA1 drive 1 partition
0), but that's nonstandard and we got rid of it later.  (I was
going to move the extension into the upper halfword of R10, since
it's normally zero, but we haven't needed it since then. . . .)
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at maryland