Subject: Re: netbsd/dos on same disk
To: None <port-i386@NetBSD.ORG>
From: Mike Long <mike.long@analog.com>
List: port-i386
Date: 08/16/1995 16:30:13
>Date: Wed, 16 Aug 95 12:22:29 PDT
>From: greywolf@tomcat.VAS.viewlogic.com (James Graham (Captech))
>#: From: Brian Leonard <paranoid@texas.net>
>#: Date: Wed, 16 Aug 1995 11:40:42 -0500 (CDT)
>#:
>#: What's the correct way to label a disk so netbsd can mount dos partitions?
>#: Everything I've tried has either munched the partition table, or given me
>#: "device not configured" when I mount the dos partition (yes, msdosfs is in
>#: the kernel).
>
>I ran into this once, and the trick seems to be to start your DOS partition
>on the NetBSD label at cylinder 1 (or is that cyl 0 track 1), and not
>cylinder 0 (, track 0).
cylinder 0, track 1.
Actually, it varies depending on how you originally partitioned the
disk. If you partitioned your disk with DOS' FDISK, the first
partition on the disk will start at cylinder 0, track 1, sector 1
(remember that sector numbers start at 1, cylinder and track numbers
start at 0). So if your disk has (e.g.) 56 sectors per track, then
the first partition starts 56 sectors into the disk.
Your mileage WILL vary if:
1) You didn't partition your disk with DOS' FDISK. All bets are off;
you'll have to use the partition table to find your DOS partition(s).
2) The first partition on the disk is not a primary DOS partition.
Your DOS partition(s) will be further into the disk, and you'll have
to use the partition table to find it/them.
3) The BIOS uses geometry translation to access your disk. In this
case, the sectors per track value used above must be the one the BIOS
uses instead of the one NetBSD uses.
--
Mike Long <mike.long@analog.com> http://www.shore.net/~mikel
VLSI Design Engineer finger mikel@shore.net for PGP public key
Analog Devices, CPD Division CCBF225E7D3F7ECB2C8F7ABB15D9BE7B
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