Disk geometry query

[Chris Johnson]

In article <4968 at brazos.Rice.edu> louis at asterix.drev.dnd.ca (Louis Demers) writes:
>X-Sun-Spots-Digest: Volume 9, Issue 39, message 7
>
>FOPERATOR at tekno.chalmers.se (Daniel Berglund) writes:
>>We have a spare Jasmine DirectFile 300 (CDC 94171-307, that's a Wren IV,
>>right?) which we would like to use on our Sparcstation 1. Does anyone know
>>the geometry of this disk or have a format.dat entry? There is already an
>>"CDC 94171-344" entry - is there any significant difference between these
>>disks?
>
>While the sticker might say 94171-307, a SCSI query for it's ID might
>reveal it is a 94171-9, that is  a MacWren IV. The geometry of both drives
>is probably 1409 cylinders, 9 heads, 46 sectors.  I beleive it has a
>slightly smaller capacity than the 94171-344.  I succesfully formatted one
>on a sun 4-110, but when came time to boot of of it,  I got the following
>error: sense key =2 error =5;
>
>The only difference between a Wren and MacWren is the firmware.
>
>I anyone ever got a sun 4-110 to boot off a 94171-307 (94171-9) I would
>appreciate hearing about it.

My WREN peripheral family summary says the following:

The WREN IV model 94171-344 SCSI drive has an unformatted capacity of 376
megabytes.

The WREN IV model 94171-307 SCSI drive is not specifically listed, but
the table has a number of entries where the suffix is XXX.  Thus the
94171-XXX designation may apply to this drive, in which case the
unformatted capacity is 307 megabytes.

That's a fairly big different, and probably enough to goof up the
formatting enough that it might not boot.

However, sense key = 2 is the SCSI "Not Ready" sense key.  From the SCSI
spec.:  "Not Ready - Indicates the logical unit addressed cannot be
accessed.  Operator intervention may be required to correct this
situation."

For example, is the disk spun up?  The Sun driver may not send a Start
Unit command to spin it up before trying to access it.  In this case, you
will need to jumper (or actually, probably un-jumper) the Motor start
option on the drive, so that it will spin up when power is applied,
instead of waiting for a SCSI command to tell it to do so.

Of course, this assumes that Sun is reporting the error correctly.  It
might be the "2" was the Check Condition status in the status byte
returned after the SCSI command that failed, in which case maybe the "5"
is the actual sense key (there is no standard SCSI "error" byte).  If so,
5 is Illegal Request, which means the Sun driver sent a SCSI command to
the Wren that it didn't like -- maybe bad parameters in a Mode Select
command or something.

Isn't SCSI fun?  :-)  Actually, I kind of like it.  Give me a SCSI bus
analyzer, and I'll fly in and find your problems for only a small
fortune!  No problem too small, no fee too large.

Seriously, well at least, more seriously, good luck, and if you have
specific questions, feel free to ask me via mail.


Chris Johnson                  DOMAIN:  chris at c2s.mn.org
Com Squared Systems, Inc.         ATT:  +1 612 452 9522
Mendota Heights, MN  USA          FAX:  +1 612 452 3607