My page references here are from 

Ridge, Peter M. _The Book of SCSI_. No Starch Press (Daly City, 1995).

Another book with checking out, because it gives a bit of technical
information on ESDI as well as SCSI, is

Schmidt, Friedhelm. _The SCSI Bus and IDE Interface: Protocols,
    Applications and Programming. Addison Wesley (Wockingham,
    England, 1995).

On Fri, 29 Dec 1995, Jason Thorpe wrote:

> On Fri, 29 Dec 95 22:37:40 PST 
>  "Brett Glass" <Brett_Glass@ccgate.infoworld.com> wrote:
> 
>  > The shoebox's cable doesn't even vaguely resemble a standard SCSI cable, so
>  > I'd need to improvise some hardware. Also, Sun seems to keep a defect list
>  > in the disk "label." An Adaptec on an IBM couldn't write that.
> 
> If it's the standard SCSI-2 to Really Bloody Huge SCSI cable, you can get 
> that at Fry's here in the Bay Area, so I imagine it can be found 
> elsewhere.  (Well, at least, that's the cable my ESDI shoebox uses...)

That cable is known as a `50-pin D-sub' connector, and is a standard
SCSI-1 connector known as `alternative 1' [p. 172]. However,
Alternative 1 was deleted from the SCSI-2 specification.

If you're looking to make an adapter cable, I strongly suggest you
have a look at [p. 199] or be very careful when looking at the Sun
documentation, as Sun numbered the pins in a rather unusual way.

> The Sun disklabel contains the defect list?  Maybe on Xylogics disks, but 
> I wasn't aware it kept it there on SCSI disks.  That would be sort of 
> anti-SCSI in spirit...But, I guess if the Emulex board doesn't store it, 
> it's gonna be in the disklabel ... hmm, interesting thought...

I don't believe that there is any bad block information in the BSD
disklabel. On EDSI drives, bad block information is written by the
manufacturer in cylinder 4095 (or cylinder 65535 if you're using
extended addressing), but I'd gathered that the SCSI controller
was supposed to compensate for this sort of thing automatically.
If it doesn't translating this information could well be interesting,
as the bad block information on an ESDI drive is actually given as
a number of bytes and length past the index mark on a track.

cjs

Curt Sampson    curt@portal.ca		Info at http://www.portal.ca/
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