*BSD News Article 16675


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From: ivie@cc.usu.edu
Newsgroups: comp.os.386bsd.questions
Subject: Re: [NetBSD] installing with DOS
Message-ID: <1993May31.094722.68786@cc.usu.edu>
Date: 31 May 93 09:47:22 MDT
References: <C7vu5z.EtM@cvt.stuba.cs> <1ud4r6$l80@stimpy.css.itd.umich.edu>
Organization: Utah State University
Lines: 62

In article <1ud4r6$l80@stimpy.css.itd.umich.edu>, altitude@css.itd.umich.edu (Alexander King Tang) writes:
> Valo Roman (valo@cvtstu.cvt.stuba.cs) wrote:
> : Because when I finished the base installation, my dos partition gone away !!!
> : Running fdisk again didn't help, it told me that there isn't enough space to
> : create dos partition.
> 
> table.  I said NO this time.  When it was supposed to reboot off the hard
> drive, it booted off my dos partition, and the non-dos partition wasn'te even
> in fdisk, so I couldn't make it active. I did it again (Take 3) I did 1 meg
> dos, 2 meg offset, and ok to overwrite dos partition table.  Once again, my
> dos partition is gone.  What happened????  Thanx..alex...

I spent about four hours a couple of weekends ago getting NetBSD and DOS to
live together. 

When you tell NetBSD to not overwrite the DOS partition, it puts the A5 
partition-type marker in the partition table, but leaves the rest of the
partition entries zero.

I wound up doing the following:

	- Start with DOS only on the drive, at the _end_ of the drive.

	- Using Norton, suck the DOS boot block and partition table from
	  track 0 into a file.

	- Install NetBSD on the first part of the hard drive, letting it store
	  its bootblock in block 0.

	- Using Norton, suck the bootblock off and stash it in a file.

	- Copy the DOS bootblock that you stashed back onto the harddrive
	  using Norton.

	- Hand-edit the partition table to add the NetBSD partition.

Here comes the fun part:

	- Copy the NetBSD boot block that you stashed in a file onto the
	  harddisk in the DOS partition; in other words, make a DOS file
	  on the hard disk that contains the NetBSD boot block.

	- Using Norton and a calculator, locate the physical address (cylinder,
	  head, sector) of the file.

	- Using Norton, build a bogus one-sector partition that points at
	  the DOS file.

	- Of course, make the DOS file containing the NetBSD boot block
	  System, Hidden, and Read-Only.

When you boot the bogus partition, it will read the NetBSD boot block from the
DOS file and jump to it. The boot block will then read block 0 from the hard
disk, find the NetBSD partition, and boot it.

Not much fun, but it works...

And with just a few hours more, I was able to make the boot block survive
the Windows/NT installation procedure.

Roger "There must be a better way" Ivie
ivie@cc.usu.edu