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From: rubin@topaz.RUTGERS.EDU (Mike Rubin)
Newsgroups: net.bugs.4bsd,net.bugs
Subject: WARNING: Ultrix 1.2 upgrade
Message-ID: <4940@topaz.RUTGERS.EDU>
Date: Fri, 9-May-86 12:18:42 EDT
Article-I.D.: topaz.4940
Posted: Fri May  9 12:18:42 1986
Date-Received: Sun, 11-May-86 00:30:04 EDT
Organization: Rutgers Univ., New Brunswick, N.J.
Lines: 16
Xref: linus net.bugs.4bsd:1766 net.bugs:726
Summary: tape read error trashes root filesystem

Before you install an Ultrix 1.2 upgrade from a tape, READ EVERY FILE
ON THE TAPE WITH "tar t" BEFORE RUNNING THE INSTALL PROCEDURE!

The install procedure renames various files that it might overwrite,
before reading in the new versions.  In particular it renames
/etc/init, /bin/sh and /bin/csh.  If it encounters a tape read error,
it doesn't put them back!  We got a tape with a bad spot, and had to
rebuild the root filesystem via the boot cassette and mini-Unix.

I'm told that if your Ultrix distribution is 1.1 rather than 1.0,
there's no way to rebuild a trashed root filesystem at all!
Apparently mini-Unix in 1.1 comes with an /etc/rc or /.profile that
immediately puts you into the install procedure, from which you can't
escape to a shell to run "restore".

DEC Software Support said both of these were known bugs that would be
fixed only by a total rewrite of the install procedures in Ultrix 2.0.