Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 25 Mar 1996 08:47:31 +1030 (CST)
From:      Michael Smith <msmith@atrad.adelaide.edu.au>
To:        shap@AURORA.CIS.UPENN.EDU (Jonathan S. Shapiro)
Cc:        dherbst@gradient.cis.upenn.edu, msmith@atrad.adelaide.edu.au, wes@intele.net, questions@freebsd.org
Subject:   Re: Booting off SCSI disks when two IDE disks also installed. (fwd)
Message-ID:  <199603242217.IAA25534@genesis.atrad.adelaide.edu.au>
In-Reply-To: <199603241715.MAA16402@eros.cis.upenn.edu> from "Jonathan S. Shapiro" at Mar 24, 96 12:15:57 pm

next in thread | previous in thread | raw e-mail | index | archive | help
A couple of points ...

> Before you installed the second drive, the adaptec controller was
> looking, saying "okay, scsi0 should become BIOS drive 0x81" and
> installing the drive in the BIOS table and the adaptec ROM disk
> BIOS as the BIOS for that drive.

... except that the SCSI disk was the newcomer on the scene.

> Actually, my guess is that it wasn't installing the BIOS with one
> drive either, and you were getting away with this by sheer luck and
> register level compatibility.

... and Adaptec SCSI controllers aren't "register level compatible" with
IDE controllers.  Or anything else for that matter.  The only SCSI
controllers I know of that were "register level compatible" were the
old Longshine LC400(?) cards that concatenated every SCSI disk you connected
to them into a huge RAID -1 IDE disk.

> If your board supports multiple IDE interfaces (many now support
> two), you might find that you are able to make things work by
> installing your 2nd drive on the 2nd interface.  Even so, be aware
> that you're playing with fire here, and not all boards will work.

Most BIOSes will consider that to be the second drive.

> I don't think that any of the fancy boot loaders will work for you.
> Most of them are dependent on the BIOS.

Almost all are inherently dependant on the BIOS.  Some BIOSes support
booting from higher disks than 0x81, Bruce's noew bootstrap code may
help with this - I haven't cut it onto a disk to try out yet.

> Jonathan
> 


-- 
]] Mike Smith, Software Engineer        msmith@atrad.adelaide.edu.au    [[
]] Genesis Software                     genesis@atrad.adelaide.edu.au   [[
]] High-speed data acquisition and      (GSM mobile) 0411-222-496       [[
]] realtime instrument control          (ph/fax)  +61-8-267-3039        [[
]] Collector of old Unix hardware.      "Where are your PEZ?" The Tick  [[



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199603242217.IAA25534>