From owner-freebsd-hackers Sat Feb 5 21:19:35 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from server.baldwin.cx (jobaldwi.campus.vt.edu [198.82.67.146]) by builder.freebsd.org (Postfix) with ESMTP id 2DBB14703 for ; Sat, 5 Feb 2000 21:19:27 -0800 (PST) Received: from john.baldwin.cx (john [10.0.0.2]) by server.baldwin.cx (8.9.3/8.9.3) with ESMTP id AAA40733; Sun, 6 Feb 2000 00:19:50 -0500 (EST) (envelope-from jhb@FreeBSD.org) Message-Id: <200002060519.AAA40733@server.baldwin.cx> X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <200002050626.XAA03255@harmony.village.org> Date: Sun, 06 Feb 2000 00:19:50 -0500 (EST) From: John Baldwin To: Warner Losh Subject: RE: Question about msdosfs Cc: hackers@FreeBSD.org Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 05-Feb-00 Warner Losh wrote: > > In msdosfs_vfsops.c we have: > || !pmp->pm_Heads || pmp->pm_Heads > 255 >#ifdef PC98 > || !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 255) { >#else > || !pmp->pm_SecPerTrack || pmp->pm_SecPerTrack > 63) { >#endif > error = EINVAL; > > What's so special about 63? Many scsi drives have more than 63 > sectors per track. The only reason that we don't see problems with > this is that it appears that CAM appears to be using a geometry with > 64 heads and 32 sectors and N cylendars. What's the justification > here? The PC BIOS (int 0x13 calls) only allows for 63 sectors numbered 1-63 for each track (cylinder). That is most likely the reason for the 63. > Warner -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.cslab.vt.edu/~jobaldwi/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message