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From: abs@nbc1.UUCP (Andrew Siegel)
Newsgroups: net.unix-wizards
Subject: How can I restore root file system in ULTRIX-32/32m?
Message-ID: <181@nbc1.UUCP>
Date: Mon, 3-Nov-86 13:26:21 EST
Article-I.D.: nbc1.181
Posted: Mon Nov  3 13:26:21 1986
Date-Received: Wed, 5-Nov-86 05:39:04 EST
Distribution: net
Organization: NBC Computer Imaging, New York, NY
Lines: 48

Is is possible to restore the root file system on an ULTRIX
machine (specifically, a MicroVAX II running ULTRIX-32m, and a
750 running ULTRIX-32)?

One method that could work is to load the "mini-system" onto the
swap partition, and use its restore command to recreate the root
file system.  This doesn't work on the MicroVAX, though, because
the mini-system does not have a restore command.  This does work
on the 750, but it takes a long time.

When I called DEC Software support about this, they couldn't
answer it to my satisfaction (like, no solution -- anyone else
having this problem with the Massachusetts Support Center?).  One
guy at the Atlanta center gave me what seemed to be a workable
solution:  grab the bootable tape copy program (tpcopy) from the
ULTRIX-32m distribution tape (TK50), and create a bootable tape
containing the root file system.  The sequence goes something
like this:

	Insert distribution TK50, extract tpcopy program:

		dd if=/dev/rmt8 of=tpcopy bs=1b

	Unload distrib tape, load blank TK50, put tpcopy and
	partition image on tape:

		dd if=tpcopy of=/dev/rmt4 bs=1b
		dd if=/dev/rra0a of=/dev/rmt4 bs=20b

	You can use the tape to copy the root partition into
	another machine by inserting the tape into that machine,
	and booting with:

		>>> B MUA0

	Remember to answer ra(0,0) when asked "To [ra(0,1)]:"

This procedure ends with a "read I/O error" when dd-ing the "a"
partition to the tape, with 794 blocks written.  The guy in
Atlanta told me that it sounds like the specified block size is
wrong, but he doesn't know the right one.  I haven't tried
booting with this tape, since I can't be sure that I'll end up
with a file system.

Any help on these difficulties would be appreciated.  Thanks.
-- 
Andrew Siegel, N2CN		NBC Computer Imaging, New York, NY
philabs!nbc1!abs		(212)664-5776