reading older disks

[steve%prd.co.uk@localhost]

I have a venerable old machine that has never progressed beyond release 4.0,
and has been little used in the past two or three years.   I set about
copying everything from its disks onto a portable drive, but the
process failed part way through, and now the machine will not boot.
Three long beeps suggest to me that there is a memory failure.

So I tried putting the disks in a caddy to read them that way, but
although the machine I am using to read them (amd64-7.0) recognises
the caddy as a SCSI device, I get:

Aug 21 16:01:49 myservcer /netbsd: sd2(umass2:0:0:0):  Check Condition
on CDB: 0x00 00 00 00 00 00
Aug 21 16:01:49 myservcer /netbsd:    SENSE KEY:  Not Ready
Aug 21 16:01:49 myservcer /netbsd:     ASC/ASCQ:  Medium Not Present

I have used this caddy to read other disks successfully; the disks
spin up, but attempts to read the label or mount them result in
"operation not supported by device" messages, e.g.

# disklabel sd2
disklabel: ioctl DIOCGDINFO: Operation not supported by device

I have wondered about jumpers on the drives, or some kind of format
incompatibility.   I can hunt around for another antique machine to
try them in, but I would welcome any wisdom you may care to offer.

--
Steve Blinkhorn <steve%prd.co.uk@localhost>