Subject: Re: SCSI-2213A partitioning problem
To: None <f.baur@kfa-juelich.de>
From: mike smith <miff@spam.frisbee.net.au>
List: port-hp300
Date: 04/30/1997 02:24:13
f.baur wrote:
> 
> HI
> 
> I recently installed NetBSD on a HP-SCSI-C2213A disk using its conventional
> disktab parmeters:
> 
> sectors/track: 56
> track/cylinder: 16
> sectors/cylinder: 896
> total cylinders: 1447
> total sectors: 1296512
> 
> etc.
> for disklabeling.
> 
> Installation went well but when booting the system, the kernel
> indicates a total number of 1296512 sectors and 1457 (!) cylinders.
> This would result in 889.85.. sectors per cylinder, obviously
> determing a bit unprecise cylinder boundaries...
> Is the hard disk badly formated, do I have to modify the disklabel
> or donīt one have to take care about the system boot message (which ist
> the case for NetBSD on PCx86)?

You can ignore the message.  The only number that's significant
for a SCSI disk is the total number of blocks.  

For most of this decade, and a lot of last, most SCSI disks
have used ZBR, or Zone Based Recording, where the number of
sectors per track varies depending on the radial position;
tracks closer to the centre of the drive have fewer sectors
than those further out, as the critical factor is media 
density, not linear velocity.

Thus, drives don't have geometries that can be meaningfully
expressed in c/h/s form, and the values that they return
are just 'courtesy' values for systems that require c/h/s
numbers.
 
--
Mike Smith  *BSD hack  Unix hardware collector
The question "why are the fundamental laws of nature mathematical"
invites the trivial response "because we define as fundamental those
laws which are mathematical".  Paul Davies, _The_Mind_of_God_