On Fri, 11 Oct 1996 18:03:56 CDT,
Bob Nestor rearranged the electrons to say:
>Sean wrote:
>
>>Why is it that I get conflicting opinions from the MacOS Mkfs
>>utility and the kernel about the number of sectors/track on my SCSI
>>disks?  Should I trust Mkfs and write a correct disklabel to the disk
>>or is this a bad idea?  BTW, I newfs'd all of my filesystems
>>except for the root, and supplied the sectors/track to it through
>>the -u flag.  Haven't seen any problems yet.
>
>I'm curious, is the SCSI disk in question a removable?  In reading 
>through the SCSI-2 documentation I see the Mode Sense command can extract 
>parameters from three different sets, the "Current", "Saved", and 
>"Default" values.  Mkfs always extracts the "Current" set, and I'm 
>thinking that for removable media which hasn't had a "Saved" set written, 
>these will be zero or undefined. If I'm correct, we should be extracting 
>the "Default" set for removable media if the "Current" set returns zero 
>or undefined values.  I'd like to check it out, but I don't have a Zip or 
>SyQuest drive.  I haven't looked into the type of values being extracted 
>my "newfs" running under NetBSD though, so I may be off base here.  Can 
>anybody else shed some light on this for me?

Actually, this is a fixed geometry drive.  My problem is that
FWB tells me that the drive has 111 sectors/track, but disklabel
(I'm not exactly sure how disklabel is getting its info) says that
it is only 110 sectors/track.  What further complicates this is
that Seagate's own web page says that the drive is 110 sectors/track.
I went with FWB's analysis, made my partitions accordingly, and
used newfs -u 111 to make the filesystems (except for the root, which
I used Mkfs, and Mkfs pre-guessed 111 for whatever reason.)

This isn't the first time I've seen this discrepancy, as I've also got
an SE/30 with 2 identical drives which for whatever reason disklabel
thinks has much fewer sectors/track than FWB tells me.

What gives?

Sean

p.s. is it a good idea to write the "correct" disklabel?

__________________________________________________________________________
Sean Sweda                        :            Owner, Motor City Marauders
sweda@us.itd.umich.edu            :   1994 Internet Baseball League Champs
http://www.umich.edu/~sweda       :                     http://www.ibl.org
__________________________________________________________________________