cfchiesa@bsu-cs.UUCP (Christopher F. Chiesa) (11/08/87)
I've just gotten thoroughly disgusted with my Percom AT-88 SS/SD 5 1/4" floppy
drive. It's been screwing up my disks more and more over the past few months,
and I finally "caught it in the act" today.
Situation: I copied a large (200+ sectors) file onto a disk which turned
out not to have enough free sectors (neglected to check in advance), resulting
in error 162 - "Disk Full." Issued "DELETE filename.ext" command. Normal
I/O sounds, then repeated "buzz-clunk" of "unreadable sector." Examined disk,
found sectors 685 and up unreadable with Error 144, "invalid 'DONE' byte".
Tried to patch file by adding next-sector field of 00 (end-of-file), but
was unable to write formerly-readable sectors. Was THEN unable to READ
formerly-readable sectors. Drive had turned a "good" sector into a "bad" one
right before my eyes. Has made many of my disks unreliable.
Error appears to occur primarily with high-end (600 and up) sectors, when it
occurs (I was able to write that file to begin with, but glitched when trying
to alter it later). NO problem at ANY time with low and mid-range (360's)
sectors.
1) I'm hoping this is just a case of a dirty head: hasn't been cleaned
or otherwise maintained since I bought the drive in mid-1983. Can
anyone offer opinions on the likelihood of this being the cause?
2) Can anyone recommend a drive-head-cleaning procedure or product (with
vendor info, if possible)?
3) I use a Q-Tip saturated in rubbing alcohol to clean the heads of my
audio equipment; would this be satisfactory for the disk head, or is
it more delicate? Would like to know before just TRYING it.
(Would someone, somewhere, please just plain REPLY to this, so that I know
it's being seen? I've NEVER had a response to ANYTHING I've posted in the
whole time (a month or two) I've been posting to the net. Are you reading
me at all, world?)
Appreciatively,
Chris Chiesa, Senior, CS Dept, Ball State University, Muncie, IN
(317) 285-1517 work
(317) 288-2957 home (weird answering message but don't panic - it's just me)ruiu@tic.UUCP (Dragos Ruiu) (11/10/87)
In article <1448@bsu-cs.UUCP>, cfchiesa@bsu-cs.UUCP (Christopher F. Chiesa) writes: > > I've just gotten thoroughly disgusted with my Percom AT-88 SS/SD 5 1/4" floppy > drive. It's been screwing up my disks more and more over the past few months, > and I finally "caught it in the act" today. [ description of error ... ] > Error appears to occur primarily with high-end (600 and up) sectors, when it > occurs (I was able to write that file to begin with, but glitched when trying > to alter it later). NO problem at ANY time with low and mid-range (360's) > sectors. > > 1) I'm hoping this is just a case of a dirty head: hasn't been cleaned > or otherwise maintained since I bought the drive in mid-1983. Can > anyone offer opinions on the likelihood of this being the cause? I doubt it is just a dirty head. Your problem sounds almost identical to a problem I had on my Corona IBM clone five years ago. It had Tandon ds/dd floppy drives. The drive would consistently get errors on high track numbers, and there seemed to be no pattern to it. It was easily reproduceable but never on the same sector. Wrote fine. Errors occured only on reads. No errors on low tracks. The first thing I did was clean the heads and check the speed. You can do this too. If you physically remove the drive you will notice it should have a ring of alternating black and white spots on the flywheel. If you watch this wheel under a fluorescent lamp (You must be in a country with 60Hz power) the spots should stay still. If they don't, your drive is too slow or fast. This can be adjusted by turning a pot on the drive logic board... If it is not marked, you should find out or get a real techie to do it for you. Your other option is to find one of the many public domain disk testers. Maybe someone you know has a special disk put out by Verbatim a while ago that checks rudimantary things like speed, tracking etc... It's not perfect but if you can find it it could point out what is wrong. My experience was that you are probably out of luck. My problem eventually wound up with a disk drive technician, he tried everything he knew on it, he actually spent many days checking the logic board and everything (In those days floppy drives were expensinve!). He found zilch. Luckily he didn't charge me, because the time he spent on it would have been twice the price of a new drive. My drive tracked perfetly, passed all the analyzer disks and the logic board was impeccably clean. Under software however, SHAZAP! It might not be worth the aggravation to fix it. You should be able to find someone with an old floppy drive at an user's group meeting in your region. I have three in my basement... (Including the shazap model :-) and the prices for new ones is certainly cheap(~>$100). The new ones are *quiet* too. > 3) I use a Q-Tip saturated in rubbing alcohol to clean the heads of my > audio equipment; would this be satisfactory for the disk head, or is > it more delicate? Would like to know before just TRYING it. I was once told that rubbing alcohol had compounds that did not evaporate. I clean my stereo with floppy disk cleaner (:-) because it is the same thing as those horrendously expensive bottles they sell in stereo stores, but a lot cheaper... (a big bottle costs as much as a little stereo bottle) If anyone can confirm the rubbing alcohol, I would appreciate it.(chemists?) But be careful, poking your Q-tip in the cramped drive space, you don't have much room, even in a full height drive. $15 at your local computer store could probably save you a lot of headaches. If you insist on Q-tips, make sure you get some extra long ones. The head assembly is not glass but bay be pushed out of alignment by poking around. On some drives the head does not lift enough for a Q-tip to squeeze in. Personally, I'm very scheptical about clean- ing heads this way. Commercial kits are so much easier and safer. As far as commercial kits, make sure you look for a non-abrasive one if you intend to make cleaning a habit. This goes for your VCR head cleaner too. I've seen VCR heads damaged permanently by some of those early abrasive (sandpaper anyone :-) head cleaners. The same technique used to be used by some floppy kits (past tense I hope). Good luck. -- Dragos Ruiu Disclaimer: My opinons are my employer's, I'm unemployed! UUCP:{ubc-vision,mnetor,vax135,ihnp4}!alberta!edson!tic!dragos!work (403) 432-0090 #1705, 8515 112th Street, Edmonton, Alta. Canada T6G 1K7 Never play leapfrog with Unicorns...
hans@umd5.umd.edu (Hans Breitenlohner) (11/11/87)
Unfortunately your problem does not sound like one you can fix by cleaning the head. If you can read old disks, but newly written ones become unreadable and unwritable, I would strongly suspect that your drive speed has drifted out of tolerance. Atari packs things slightly more densely than others, and as a result drive speed is more critical. If your drive has speeded up, writing a sector may cause the sector id field of the next physical sector to be trashed. The next physical sector usually is 2 logical sectors beyond the current one. (Sectors are arranged in the sequence 1,3,5,...,15,17,2,4,6,...,14,16,18 -- at least on standard Atari drives). This may also explain why lower sectors work better: The disk may be slowed down more when the head is near the outside of the disk. Another possibility is that the part of the drive electronics which turns write current on and off is not functioning properly. This is what I would suspect if writing one sector makes more than it or the next sector on the track unreadable. There are a few experiments you could do. Get a program which checks your drive speed. If you can find an old disk that you don't care about, write single sectors and see how much of the track gets trashed. Also try formatting a new disk, and run read-write tests on it. Good luck, you might need it on this one!
root@uwspan.UUCP (John Plocher) (11/16/87)
+---- ruiu@tic.UUCP (Dragos Ruiu) writes in <147@tic.UUCP> ---- | > 3) I use a Q-Tip saturated in rubbing alcohol to clean the heads of my | > audio equipment; would this be satisfactory for the disk head, or is | > it more delicate? Would like to know before just TRYING it. | | I was once told that rubbing alcohol had compounds that did not evaporate. | I clean my stereo with floppy disk cleaner (:-) because it is the same thing | as those horrendously expensive bottles they sell in stereo stores, but a lot | cheaper... (a big bottle costs as much as a little stereo bottle) +---- Use Isopropyl alcohol, 91% by volume or better. Do NOT use the 75% shit - it does leave crud on your heads! Qtips leave fibers stuck to things, it is better to use a special cleaning disk - saturate it with isopropyl, stick it in the drive, and "format" it :-) Works wonders! (the isopropyl is also good for the audio stuff) The better sterio stores have flat, foam tipped swabs with long handles which are made for cleaning tape drives - they work OK on floppies in a pinch. Some of the cleaning kits recomend cleaning as often as weekly (shudder)! I clean the heads about once every 6 months or 6000 miles :-) as needed. If someone smokes near the drive then you might want to a) Shoot the smoker -or- b) Help him/her quit the habit (at least while near the computer) -or- c) Clean the drive more often (monthly?). -John PS. Just a wild guess on the floppy problem, try moving the color monitor away from the floppy drive - the monitor screws up the electronic signals on the floppy drive. -- Email to unix-at-request@uwspan with questions about the newsgroup unix-at, otherwise mail to unix-at@uwspan with a Subject containing one of: 386 286 Bug Source Merge or "Send Buglist" (Bangpath: rutgers!uwvax!uwspan!unix-at & rutgers!uwvax!uwspan!unix-at-request)