From owner-freebsd-hackers Fri Mar 22 18:12:20 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id SAA20771 for hackers-outgoing; Fri, 22 Mar 1996 18:12:20 -0800 (PST) Received: from godzilla.zeta.org.au (godzilla.zeta.org.au [203.2.228.19]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id SAA20766 for ; Fri, 22 Mar 1996 18:12:13 -0800 (PST) Received: (from bde@localhost) by godzilla.zeta.org.au (8.6.12/8.6.9) id NAA02403; Sat, 23 Mar 1996 13:00:30 +1100 Date: Sat, 23 Mar 1996 13:00:30 +1100 From: Bruce Evans Message-Id: <199603230200.NAA02403@godzilla.zeta.org.au> To: joerg_wunsch@uriah.heep.sax.de, terry@lambert.org Subject: Re: Adding a damn 2nd disk Cc: freebsd-hackers@FreeBSD.org Sender: owner-hackers@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk >> > In any case, a linear congruential search for the boundry conditions >> > followed by a binary search could easily find the last sector on >> > any device for you. ... >> >> How big is the chance that this will jam an good ol' ``dumb'' drive? >A plain binary search will fail at twice address wrap boundry; that's >why you can't start at 32 bit and work down with a vanilla binary >search. I think it won't quite work on many ESDI drives. IIRC _part_ of the cylinder beyond the last cylinder was readable but not writable on my drives, and the last readable and writable cylinder was one more than the number reported by the BIOS. Bruce