From owner-freebsd-hardware Wed Nov 26 04:45:58 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id EAA13852 for hardware-outgoing; Wed, 26 Nov 1997 04:45:58 -0800 (PST) (envelope-from owner-freebsd-hardware) Received: from math.berkeley.edu (math.Berkeley.EDU [128.32.183.94]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id EAA13842 for ; Wed, 26 Nov 1997 04:45:54 -0800 (PST) (envelope-from dan@math.berkeley.edu) Received: (from dan@localhost) by math.berkeley.edu (8.8.7/8.8.7) id EAA15871; Wed, 26 Nov 1997 04:45:52 -0800 (PST) Date: Wed, 26 Nov 1997 04:45:52 -0800 (PST) From: dan@math.berkeley.edu (Dan Strick) Message-Id: <199711261245.EAA15871@math.berkeley.edu> To: freebsd-hardware@FreeBSD.ORG Subject: Re: large IDE disks Cc: dan@math.berkeley.edu, kent@tfd.com Sender: owner-freebsd-hardware@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > I'm putting a 2.2 GB IDE disk in my laptop. The problem is the > > bad sector information. With the straightforward approach, you > > can only store 126 bad sectors. A lot more than that were found. > > A friend (Terry Carroll, Munich (still not on the net) > told me he used fdisk to carve his disc into 4 slices first, > then he ran bad144 * 4. > Ive no idea if this is valid or not, > no doubt other wiser people will comment :-) My attitude toward IDE drive maintenance may be seriously outdated, but here it is anyway: ("no doubt other wiser people will comment") IDE disk systems simulate an ancient IBM PC/AT ST506 disk controller with a few semi-standard extensions required to support modern disk drives. The logic that emulates the old controller is almost entirely embedded in the IDE disk drives. The behavior of an IDE drive when emulating a special controller function (such as formatting) is less well standardized. Since modern drives and modern PCs have modern performance characteristics, a literal interpretation of old drive formatting commands may be inappropriate. Vendors of IDE drives used to provide special drive maintenance programs that invoked proprietary disk drive features. If you attempted to do a low level reformatting of your drive using the standard DOS utilities, you might well end up with an inappropriately formatted disk (e.g. with sector interleaving). Reformatting an IDE disk was a bad idea unless you knew that the reformatting program was appropriate for that specific IDE disk drive. Vendors no longer provide special drive maintenance programs for IDE drives, perhaps because the DOS marketplace never really understood what it called "low level" formatting. I think they expect the end user to leave the "low level" formatting alone. If bad sectors develop, then the end user reruns the DOS FORMAT program or some other utility to remove the bad sectors from the active file system. If the "low level" format becomes really degraded, then the end user thinks the drive is busted and buys a new drive. What has this got to do with "bad144"? BAD144 is an ancient DEC standard for bad sector forwarding. It is totally inappropriate for modern drives which can have thousands of bad spots that are made invisible to unsophisticated disk driver programs by other more elegant means. I don't see anything on the bad144 man page that suggests it has been kept technologically up-to-date. I doubt that you are really expected to use it. Modern IDE drives may be smart enough to ignore the details of a low level drive command and do the "right thing" instead (including surface analysis) when you tickle them with an obsolete format command. Perhaps the thing to do is use the PC BIOS disk formatting feature and test the drive carefully afterwards (perhaps with the bad144 program). If the drive still seems to have bad spots or has developed antisocial behavior (like bad performance), buy a new one. Better yet, buy a SCSI card. Dan Strick dan@math.berkeley.edu