Subject: Re: i386 booting, take 2
To: None <firstname.lastname@example.org>
From: Wolfgang Solfrank <email@example.com>
Date: 09/21/1998 19:37:11
> Improve `by a bit'? As opposed to what? No other mechanism was
> proposed that would even work on a significant fraction of modern
Hmm, I thought I had proposed something that would have improved the
situation a bit, too. Maybe, your proposal improves it on more machines
than mine, but nonetheless...
> Sorry, but I don't buy this. The BIOS doesn't look at the partition
> table; it just loads the MBR, checks the `signature', and runs it.
> (There may also be some tweaks for `virus detection', such as checking
> the first instruction.) I have tested dozens of machines, and not a
> single one did anything else here.
> I need firm proof, not just anecdotes.
As an aside (one might look at this as an anecdote as well :-)), we've got
here some machine with an LS120 drive, and with this machine, the BIOS, after
having read the first sector of the disk, assumes, that that's the first
sector of a FAT filesystem and patches the values for sectors/track,
number of heads and a byte at offset 0x24 (which doesn't make sense to me).
Actually, this patching doesn't make sense to me at all...
> I don't believe that's possible. In particular, unless you're doing a
> `whole disk' installation on a newer machine (one with `large disk'
> support -- again, assuming the boot block is fixed), then you *have*
> to deal with the 1024 cylinder limit.
I'm not sure what you are talking about, when you are saying "`whole disk'
installation on a newer machine". If you've got a "newer machine", you
could install NetBSD anywhere on the disk (given the proposed modified
fdisk mbr, boot sector and boot program), provided you make sure that
the MBR code stays the same as the one that NetBSD will write there.
ws@TooLs.DE (Wolfgang Solfrank, TooLs GmbH) +49-228-985800