Imaging SCSI hard disks

From: Jules Richardson <julesrichardsonuk_at_yahoo.co.uk>
Date: Wed Sep 1 05:52:16 2004

On Mon, 2004-08-30 at 15:00, classiccomp-tech_at_bouncy-castle.demon.co.uk
wrote:
> I've a couple of SCSI hard drives (DEC RZ24-S) that I'd like to do a
> complete image of. If I stick them in a linux box and do a dd on them,
> will it copy all the blocks from the device, or am I going to get
> messed around by the PC BIOS INT13 doing stupid CHS translation on the
> otherwise LBA device and potentially miss some blocks at the end of
> the device? Does Linux go through the SCSI cards BIOS or does it talk
> directly to the carsd hardware & so do raw LBA?

Linux will just use the SCSI card's hardware - it won't touch the PC's
BIOS at all, so you've got nothing to worry about there.

> Of course, it probably all depends on the version of linux I'd use.

Not really. Anything from the last 5 or 6 years (maybe longer) should
have support for the 2940 controllers, and procedure will be the same on
all of them.

Actually, I think the first time I ever did this was with the SCSI
interface that was on board a Pro Audio Spectrum sound card way back
when and it worked fine even then...

> Any suggestions?

My only experience is really with Slackware and Redhat (and SLS in the
early days!) but they shouldn't give you any problems. Freebsd is
another option and should just work the same way as far as what you're
needing to do.

> (note, I've not actually got a linux box setup to do this at this
> point in time, I've an AHA2940 lined up to stick in a PC and then
> figure out the wonderfull world of SCSI on linux...)

It all just works - don't worry about it :)

Aside - the DEC drives are formatted to 512 byte sectors aren't they?
I've got some SCSI drives formatted for Acorn hardware that I need to
image, but they're formatted to 256 byte sectors and I'm not sure if I'm
going to run into problems there - probably all sorts of assumptions are
made in software about drives using 512 byte sectors, and I don't think
many SCSI drives will even format to 256 bytes per sector these days...

cheers

Jules
Received on Wed Sep 01 2004 - 05:52:16 BST