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From: rcodi@chudich.co.rmit.oz (Ian Donaldson)
Newsgroups: comp.unix.wizards
Subject: Re: 4BSD file system structure
Message-ID: <1712@minyos.xx.rmit.oz>
Date: 15 Nov 89 23:43:54 GMT
References: <3410@netcom.UUCP> <20643@mimsy.umd.edu> <1602@minyos.xx.rmit.oz> <6509@lynx.UUCP>
Sender: news@minyos.xx.rmit.oz
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m5@lynx.uucp (Mike McNally) writes:

>rcodi@chudich.co.rmit.oz (Ian Donaldson) writes:

>Another couple of disadvantages:

>    Bad block in the vmunix partition.  I see no way the firmware could
>    cope.  (Of course, if the disk is a decent SCSI drive, is will do
>    its own remapping and this problem almost goes away.)

The firmware could process the bad block map in the 'a' partition
quite easily... in our systems its just next to the partition table.

Of course the only blocks that can't be fixed are the blocks containing
the bad block map unless you put a special case in for that (eg: if
the bad block map sits in a bad block then try a fixed list of other
blocks)

>    I make a new kernel.  I install it in its special partition.  It
>    fails because I'm slightly ignorant and screwed up.  I lose big.

No problem.  Just boot one you have backed up on another boot partition.
If you don't have one, go to your distribution tape and run standalone
copy to copy one in to some boot partition.  Its even easier than having
to load an entire root partition into the swap device just so you can
boot it to find a kernel to copy back to your real root!  (like you
do with SunOS)

Ian D