Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!petrus!bellcore!decvax!decwrl!sun!chuq From: chuq@sun.uucp (Chuq Von Rospach) Newsgroups: net.micro.mac Subject: Re: Bad Disk Block Horror Story Message-ID: <3117@sun.uucp> Date: Sat, 4-Jan-86 15:17:20 EST Article-I.D.: sun.3117 Posted: Sat Jan 4 15:17:20 1986 Date-Received: Mon, 6-Jan-86 03:10:54 EST References: <8601030325.AA25594@kim> Organization: The Hackers Line Lines: 76 > I just found out that a disturbingly large number of my floppy disks have > bad blocks. > But wait again, it is worse yet. Many times I've had to scavenge and > reformat disks when they've been trashed such that "Some files couldn't > be read and were skipped", "This disk is unreadable. Do you want to > initialize it?", or "The file copy didn't work. Try copying to a different > disk". The bad ones were ONLY the latest ones I've found. > I don't think I'm the only one with these problems. Just about everyone I > know with a Mac sooner or later finds himself with a file or disk that is > corrupted. > You too probably have a fair number of disks that are screwed up. No? > You probably just don't know it yet. Macintoshes seem to suffer from this > problem with distressing regularity. Why? What could cause this? I've never > had such disk problems with IBM PC disks. > I urge you all to check every one of your disks. If you would mail your > findings to me, I will summarize the results. Please report: > > 1. The number of bad disks you find, broken down according to the amount > of use each is given. > 2. How long have you had your Mac? > 3. Estimate the number of bad disks you've encountered during this time. > > Also, can anyone explain why these problems occur? Well, at Gordon's suggestion, I went rummaging through my collection. I've got somewhere between 150 and 200 disks. In checking about 75 disks (about 10 blank and initialized ones, all of the ones I use more or less constantly, and a random conglomeration of the disks in my archive including a lot of the Apple supplied software supplement disks) I found one bad block, which was track 33, sector 0 of my Rogue distribution disk -- I bet that is what they used for copy protection at that. Everything else came through with no problems at all. I the last year that I've had my Mac, I've thrown away one disk that wouldn't re-initialize after being used for a while. I've never had a disk related failure, never had software fail because of a bad write, never lost a file due to a disk failure. Most of my disks are Sony's the I buy in Bulk. I've also bought Apple disks (early on, when they were the major supplier), Maxell, and a few other random boxes. I also have all the Apple supplied supplment disks. Now I do a couple of things that may be a bit different. First, I clean my disk heads fairly regularly (although it has been almost a month, come to think of it). I also use a disk initializer on all my blank disks rather than just using 'Erase Disk'. When I finish with a disk, it goes to the bottom of my free pool and when it resurfaces it gets initialized. Since I'm constantly re-arranging my system disks (adding DA's, fonts, or removing them again or something) I see to recycle those fairly regularly also. I also try to keep my disks away from magnetic things that might make them unhappy. I'd suggest that Gordon's problem is one of a few things: o dirty disk heads -- especially if the problem sectors move around. o misaligned drives o power surges o something magnetic (don't keep your disks on your stereo speaker, be careful with things like Bart ticket readers, you probably don't want to keep yours disks on top of your Mac for both heat and magnetic (from the CRT flyback transformer) reasons. I'd guess that he is a special case, not the normal situation (if he was, I think we'd have heard a lot of screaming from the users about blown disks, and it just doesn't happen). I DO suggest that people check it out, though -- if you've got a problem, you want to know so you can get it fixed. If you aren't cleaning your disk heads, go out, buy a kit (about $15) and DO IT. chuq -- :From catacombs of Castle Tarot: Chuq Von Rospach sun!chuq@decwrl.DEC.COM {hplabs,ihnp4,nsc,pyramid}!sun!chuq It's not looking, it's heat seeking.