3B2 Horror story - will it ever run?

Flint Pellett flint at gistdev.gist.com
Sat Feb 9 03:11:38 AEST 1991


almquist at cis.udel.edu (Squish) writes:

>From: "Bradley E. Smith" <brad at bradley.bradley.edu>
>>Reboot the diskette and instead of 1,2,3 type 'magic mode'. Then select
>>the 'shell' option.  This will give you shell access on the floppy.
>>you then might be able to mount your root device and edit the password
>>file.

>WOW!  Att machines are certainly off the beaten track.  You won't find these
>funny (or fun?) modes on a Vax or Sun.  Anyways, I go into 'magic mode' and
>then select the 'shell' option.  Hurray!  I've got the root prompt it worked.
>Could it be my lucky day?  NO!  Nothing exciting is on the 1st disc.  No,
>mount, tar, dd, nothing.  Can anyone send me a bootable disc with mount on it.

If you want to mount something, you have to do something like this:

# fsck /dev/idsk00
# fsys -m /install /dev/idsk00

(You may not need the file system check fsck.)
That mounts the hard disk's root file system onto the floppy's /install.
You then get an error message that is quite misleading, and should be
ignored- something like /dev/idsk00: no such file or directory.  The
error message apparently comes from not mounting on /mnt (you can't use
/mnt since there isn't one).  Now you have root mounted, and you can get
to some real tools in /install/etc and /install/bin, but it will still
be painful, and you may have to change a lot of env vars as you go to
do stuff.   For example, if you want to use vi you'll quickly find out
that there isn't enough spare space on the floppy in the TMPDIR, etc.
to edit anything of any size.

To unmount, use:

# fsys -u /dev/idsk00

PS: be very careful what you do in situtations like this: if things are
screwed up you can easily make things worse if you don't think about
every move first.  That's probably why AT&T won't advertize this ability,
they don't think most of us peasants in the field know enough to not
mess themselves up worse.  But if you've got something simple to fix
(like a zeroed /etc/passwd file, for example) this can save lots of time.
-- 
Flint Pellett, Global Information Systems Technology, Inc.
1800 Woodfield Drive, Savoy, IL  61874     (217) 352-1165
uunet!gistdev!flint or flint at gistdev.gist.com



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