Format of 386 Unix boot diskette

[Chris Lewis]

In article <1990Jan29.220409.3932 at banzai.PCC.COM> john at banzai.PCC.COM (John Canning) writes:
> In article <323 at ohsuhcx.ohsu.edu> bj at ohsuhcx.ohsu.edu (Bill Jackson) writes:

> >Does anyone have information on the format (layout of disk, cpio/dd/tar etc) of
> >the boot diskette used to load AT&T Unix V 3.2.2 on the 386 WGS machines?

> The initial disk is a mountable file system.  

Correct...

> I do not know how to make a floppy disk bootable.

The simplest approach is to simply put the boot diskette into the drive,
and dd the whole disk into a file somewhere.  Put a new diskette in,
(physical format if neccessary) and dd it back out.  On our machine the
appropriate device is /dev/dsk/f0q15dt, John uses /dev/dsk/f0.  Use big block 
sizes to make it go fast.

Then, if you want to modify the new copy, mount it, as in

	/etc/mount <whichever device works for you> /mnt

And diddle.  But I would strongly recommend not removing anything from
it, even though you'll probably not have much space on it, unless you
know *exactly* how the boot process works.  /etc/init, inittab etc. etc.
are all neccessary for the boot.  Makeing it do a from-tape
installation shouldn't be too hard - our boot floppy has all of the
questions/stubs for it *except* the tape driver in the kernel....
-- 
Chris Lewis, Elegant Communications Inc, {uunet!attcan,utzoo}!lsuc!eci386!clewis
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