hamachi@KIM (Gordon Hamachi) (01/03/86)
I just found out that a disturbingly large number of my floppy disks have
bad blocks. Using the ScanDisk utility, I tested all 131 of my disks and
discovered 7 with blocks that couldn't be read. But wait, it is worse than
it looks. Two of 17 "work disks" were bad, and 5 of 59 "archive disks"
were bad. 55 other disks came from Apple's software supplement, and have
never been touched.
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.
But wait one more time, it is again worse! There are likely many more bad
disks in my collection. Further checking shows that many of the errors are
"soft". For each bad block on each disk I list the number of times (out of
10) it couldn't be read. For example, for disk 6 in 10 trials there were
29 bad block reads distributed over 3 different blocks.
Disk Times each block was bad in 10 trials
1 3, 4, 10, 9, 9, 2, 1
2 2, 1, 1
3 10, 3, 7, 3
4 10
5 8
6 10, 10, 9
7 2
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.
Some possibilities:
1. Program bug
2. Finder bug
3. Power glitch or other "act of god"
4. External magnet, x-ray, etc
5. Bad disk medium
6. Physical daage to disk
7. Bad disk drive
8. Bad disk drive design
9. User error (turning off power during a disk write, etc)
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?
Gordon Hamachi
(E-Mail: ucbvax!hamachi, hamachi@berkeley.edu)
(USMail: Computer Science Division, Evans Hall, Univ. of Calif, Berkeley 94720)ix21@sdcc6.UUCP (Mr. Monk) (01/03/86)
I had a problem with bad disks too. One day I kept getting "This is not a Macintosh Disc, reinitialize?" query to a bunch of discs. Reintialization would always fail. At first I thought it was all the discs made by a certain company that were bad because all of all that company's discs went bad, while all of those of other companys remain good as I tested them. So I threw out all the bad discs. Then stupid me realized that it was not the companys fault it was just that all the discs that were being placed in the external drive were failing; it was just an incredible coincidence that I place all of that particular company's discs in the external drive. Well I took the external drive to my friendly neighborhood Apple dealer and was given an estimate of about $112 for the minimum labor charge of one hour and the cost of replacing the sony drive with in the external disc drive. It turned out that the Sony drive was faultless; the problem was in the cable that connected the drive to the Mac. I ended up paying ten dollars more than the estimate because the PART COST FOR THE CABLE IS TEN DOLLARS MORE THAN THE PART COST OF THE SONY DRIVE. I was absolutely stunned when the dealer explained that to me. Other than that experience I have never had a problem with a blank floppy disc that I bought failing for a reason other than negligence. (You see I have a sister who likes to use my discs as coasters. My neglience is not connecting my sister to one end of a high voltage power supply.) -- ---- David Whiteman, University of California, San Diego
chuq@sun.uucp (Chuq Von Rospach) (01/04/86)
> 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.
ems@amdahl.UUCP (ems) (01/07/86)
I have discovered that sometimes the '... do you want to initialize...'
message comes from sloppy insertion. On my internal drive, I have
gotten the error message, ejected the disk, put it back in; and
all was fine again. The difference? If the disk was flexed too
much when sliding the lock tab, the problem would manifest; also
if I pushed oddly on the disk during insertion. The solution?
Take it out, flex it back and forth a little, put it in again
with minimum finger pressure.
My conclusion? Either my drive is modestly out of alignment
or the fundamental design of the disks is slightly flakey.
--
E. Michael Smith ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems
This is the obligatory disclaimer of everything.fbr@utastro.UUCP (Frank Ray) (01/07/86)
Regarding magnetic sources that can scramble disks: In most telephones there is an electromagnetic bell which can, if place near enough (like on top of) to a disk, cause spurious patterns of information. Keep your disks away from ringing telephones. Probably half an inch is enough, but better to be safe than scrambled. fbr
briand@tekig4.UUCP (Brian Diehm) (01/09/86)
>If you aren't cleaning your disk heads, go out, buy a kit . . . and DO IT. > >chuq Well, head cleaning is good advice, but the kits are another story. I've had disk failures occur suddenly, at which time I've used a kit to clean the head. No dice. Then, immediately, I've torn apart the disk drive and cleaned the head directly with a cotton swab and Freon TF (I assume alcohol would also work). Presto - working disk. The point is that THE KIT FAILED TO CLEAN THE HEAD! This occured more than once, so I've never bought another kit. It is possible that cleaning kits will work but only as preventative maintenance, I don't know. Chuq is definitely right about keeping those heads clean! For net info, the kit I used was made by Check-Mate Computer Suplies Inc., Randolph, MA. It's a clever kit, it will handle single or dual-sided drives, it just doesn't work! -Brian Diehm Tektronix, Inc.
jww@sdcsvax.UUCP (Joel West) (01/10/86)
In article <2492@amdahl.UUCP>, ems@amdahl.UUCP (ems) writes: > I have discovered that sometimes the '... do you want to initialize...' > message comes from sloppy insertion. On my internal drive, I have > gotten the error message, ejected the disk, put it back in; and > all was fine again. > > My conclusion? Either my drive is modestly out of alignment > or the fundamental design of the disks is slightly flakey. I've had a lot of "do you want to initialize" problems, and most are along the lines of ems's comments. I always give a disk at least a 2nd chance.
bart@reed.UUCP (Bart Massey) (01/11/86)
> > 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. > > 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'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 I didn't even bother to check all mine -- I already knew I had quite a number of them with the problem Gordon describes, and the first one I checked had one bad block. I tend to agree with Chuqui's comments about what might be wrong, although I would also add possible drive speed variation problems to the list -- the speed control method used is none too sane. I suppose I should clean my drive, but the fact remains -- the Mac 3.5" drives are MUCH less resilient than any 5.25" drive I've ever worked with. At Reed, we routinely have problems like those Gordon described, plus quite a problem of incompatibility of disks formatted on one mac with another mac! The most likely causes of this are drive speed differences or badly aligned drives, but since there is no way to adjust the drive speed or realign the drive except to mail it back to Apple (or so our service person tells me) it's kind of a moot point -- we just can't afford to do that in either time or money. Three cheers for the rumored SC(u)SI port, if it becomes reality -- I'se gunna just git a big hard disk, and ignore the 3.5" diskses forever, except for backups and interchange with other machines... In sum, we at Reed have heard a LOT of screaming from users about blown disks. Just thought I'd add my two bits. Bart Massey ..tektronix!reed!bart "Someday, my son, all this will be yours." "What, the curtains?" --Monty Python
hogan@rosevax.UUCP (Andy Hogan) (01/16/86)
> >If you aren't cleaning your disk heads, go out, buy a kit . . . and DO IT. > > > >chuq > > Well, head cleaning is good advice, but the kits are another story. ..... > The point is that THE KIT FAILED TO CLEAN THE HEAD! This occured more than > once, so I've never bought another kit. It is possible that cleaning kits > will work but only as preventative maintenance, I don't know. > Our field service group has investigated several head cleaning kits and concluded that IF used regularly AND properly, they help as a preventative measure. They then concluded that we should not reccommend that our customers use them, because we don't think both "if's" above can be easily met in the field. Especially since the instructions that come with them generally try to get you to use too much cleaner (usually alchohol) and use the kits too often. I recommend the harder, but better, method of cleaning by hand with swabs and alcohol. > Chuq is definitely right about keeping those heads clean! > -Brian Diehm Uh, yeah, he sure is. Thanks for the reminder, both of you, I'll do mine tonight. (When was the last time, hmmmmm.....nah, I must'a done it since then..........) -- Andy Hogan Rosemount, Inc. Mpls MN path: ...ihnp4!stolaf!umn-cs!mmm!rosevax!hogan Working is not a synonym for Quality.