Verily did Matt Ragan write:

> David Jones wrote:

>>> 	Here's a question... how do I deal with a disk w/o geometry?
>>> I have a SCSI disk made by IBM that won't respond to the driver's
>>> geometry request.  I would suppose that I have to figure it out... and
>>> then somehow communicate this in the disk label?  Some hints would be
>>> nice.  I don't think that it will be too great a problem to find info
>>> on the true (or close to true) nature of the disk.

>>The actual geometry of a SCSI disk is irrelevant.  You need only come up with
>>something having same or fewer blocks.

>>One way might be to write an absurdly big label (e.g. 4GB disk), then dd to
>>the disk and write down the block offset when the writes fail due to being
>>beyond end of medium.  Then figure the label from that.

>>BTW, if this IBM disk is so nonstandard as to not respond to the geometry
>>command, don't expect it to work right on NetBSD.

> Actually, they will, as long as you write a somewhat reasonable disk label.
> I've got a smaller IBM drive that does the same thing (mode sense fails 
> trying to read the geometry; ya gotta love a manufacturer that deliberately 
> doesn't conform to standard SCSI conventions) on an i386 box that works 
> just fine.  Every time I boot I get the error:

> sd1(ahb0:1:0): illegal request, data = 00 00 00 00 24 00 00 00 00 00 00 00 01
> 32 00 00 00 00 00 00 00 00 00 00
> sd1: could not mode sense (4); using fictitious geometry

> but it will find and use the geometry written on the disklabel:

> sd1 at scsibus0: 382MB, 382 cyl, 64 head, 32 sec, 512 bytes/sec

I have an IBM DPES-31080 1Gig drive at home (NetBSD/i386) and at work
(NetBSD/sparc).  I encountered the 'no geometry' problem when setting
the one at work up with SunOS.  My solution to it was to log into my
home machine, check the `dmesg` parameters, and plug then into the
SunOS `format`.  They worked like a charm (just remember to use <cyl>-2
for the "useable cylinders" query or whatever the first question was).

FWIW, the DPES-31080 params are:

bt0 targ 0 lun 0: <IBM, DPES-31080    !t, S31Q> SCSI2 0/direct fixed
sd0 at scsibus0: 1034MB, 4903 cyl, 4 head, 108 sec, 512 bytes/sec

I don't know why I get a !t, but I see it on a couple of machines at
work when the Adaptec controller polls the SCSI devices, also have seen
a !q as well.  Appears to be harmless *knock on wood*.

-- Rob
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