Subject: Re: Disk Tab for SCSI Maxtor 7345 (340MB)
To: None <port-vax@netbsd.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: port-vax
Date: 11/27/1998 08:55:41
> I have the geometry stuff for this scsi drive.
> I am not sure what the disktab entry should look like because the
> varying number of sectors per track.

disktab was designed before ZBR disks and cannot accurately describe
such disks.  For various other reasons, such as track caches and
sometimes even host interfaces that can't keep up with the medium,
accurate geometry matters less now than it did then.  (For disks which,
like SCSI drives, are addressed as a big array of sectors - as opposed
to c/h/s addressing, for example - incorrect nhead and nsect values
hurt nothing but performance.)

What I normally do is declare nhead=32 nsect=64, which gives me 1MB
"cylinders"; I then declare a number of cylinders that's the disk's
actual capacity rounded up to the next megabyte boundary, and let it go
at that.

					der Mouse

			       mouse@rodents.montreal.qc.ca
		     7D C8 61 52 5D E7 2D 39  4E F1 31 3E E8 B3 27 4B