Date: Tue, 12 Nov 1996 00:23:27 -0800 From: Darryl Okahata <darrylo@hpnmhjw.sr.hp.com> To: "Michael L. VanLoon -- HeadCandy.com" <michaelv@MindBender.serv.net> Cc: BRETT_GLASS@infoworld.com, Harlan Stenn <Harlan.Stenn@pfcs.com>, rschof@mccomm.nl, freebsd-hardware@FreeBSD.org Subject: Re: After changing to an AHA2940 I can't boot the kernel. Message-ID: <199611120823.AA113677008@hpnmhjw.sr.hp.com> In-Reply-To: Your message of "Mon, 11 Nov 1996 23:20:12 PST." <199611120720.XAA01622@MindBender.serv.net>
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Michael L. VanLoon (michaelv@MindBender.serv.net) wrote:
> >Most likely problem: the sector mapping on one controller is different from
> >that on the other.
>
> This is theoretically possible. But in the Real World, I have never
> seen this happen, juggling drives between a BusLogic BT747s, a BT956c,
> an Adaptec 2940UW, and an NCR 53c810. I think I mixed a 1542 in there
> a few times, too, but I'm not positive.
I've seen it between a 1542CF and an NCR815. The Adaptec used a
C/H/S geometry like C/64/32 or C/255/63 (I forget which -- perhaps it
depends on the "support disks >1GB" setting?). My NCR815-based
controller (a DTC 3130B) appears to use a very different geometry:
C1/H1/63, where:
H1 = int((disk_size / 63 + 1023) / 1024)
C1 = int(disk_size / (63 * H1))
disk_size = total size of disk in sectors
With the NCR, my Quantum 4GB Atlas has a geometry of 1017/131/63, and my
Quantum Fireball 1280S has a geometry of 1019/39/63. These are quite
different from the Adaptec geometries.
Do the NCR geometries vary from controller to controller?
-- Darryl Okahata
Internet: darrylo@sr.hp.com
DISCLAIMER: this message is the author's personal opinion and does not
constitute the support, opinion, or policy of Hewlett-Packard, or of the
little green men that have been following him all day.
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