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From: j@bonnie.heep.sax.de (J Wunsch)
Newsgroups: comp.periphs.scsi,comp.os.linux.hardware,comp.unix.bsd.freebsd.misc,comp.os.linux.setup
Subject: Re: SCSI PCI host adapter
Date: 8 Sep 1995 13:38:13 +0200
Organization: Private U**x site, Dresden.
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Message-ID: <42p9v5$hbn@bonnie.tcd-dresden.de>
References: <418r3m$9c6@trauma.rn.com> <42ea9k$1sd@trauma.rn.com> <danielDEE700.Guv@netcom.com> <42lg2j$pks@news.parc.xerox.com>
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Xref: euryale.cc.adfa.oz.au comp.periphs.scsi:36931 comp.os.linux.hardware:15137 comp.unix.bsd.freebsd.misc:5652 comp.os.linux.setup:19484
Peter MacLeod <macleod@adoc.xerox.com> wrote:
[disks do not work any longer after replacing the SCSI controller]
>In the case of real operating systems which have SCSI managers and drivers,
>and ignore the whole BIOS mess, I would think that disks swapped between
>cards would be compatible, especially if one didn't try to boot off of the
>SCSI drive. This might be naive, however--many card vendors don't understand
>the purpose of a standard like SCSI, and might "be clever" and break it for
>no good reason.
Booting is just the only issue. It's done by the firmware (or: BIOS),
so the operating system cannot do anything here. For a non-boot disk,
you are free to label it however you like, and they should be
exchangeable between different controllers.
For bootable disks, those where the operating system boots off sector
0 (ie., the MBR is the bootstrap of the operating system itself) will
be exchangeable, too, as long as the BIOS idea of the geometry is
sufficient to load the bootstrap. (For *BSD, the bootstrap is 15
sectors long, so every usual geometry idea will work.)
Needless to say, you cannot share such a disk with messy dos.
(I can easily proof my claim, my FreeBSD is booting this way. No
[valid] fdisk partition table, no nothing, it boots straight off
sector 0.)
--
cheers, J"org private: joerg_wunsch@uriah.heep.sax.de
http://www.sax.de/~joerg/
Never trust an operating system you don't have sources for. ;-)