Screeching 5 1/4 FDD

-> On Thu, 5 Oct 2000, Lawrence Walker wrote: -> -> > I have a hard to replace dsdd floppy disk that produced a -> > screeching noise while attempting to read it on a win98 box under -> > Dos using a Dos program. The screeching is caused by lack of lubricant on the disk surfaces. The drag caused by this will sometimes slow the disk rotation enough to cause errors, even though enough of the original disk surface remains to allow reading. -> >I quickly removed it and tried to read it -> > on another Dos box also with a HDFDD. No screech but only the -> > directory was readable, not the contents. I checked the original -> > FDD again using a scrap dsdd floppy and had no trouble with it. -> > Anyone have any thoughts as to what would have caused this ? -> -> Whenever I have heard that horrid squeal, it has been followed with the -> disappearance of the magnetic media on a track or cylinder. Whenever I've had this problem occur it has been caused by improper storage of the subject disk, usually in an area of high humidity and warm temperature. When the disk surface shows a white splotching/spotting, lighter brown splotching or other discernible discoloration, it is caused by a mold or fungus that eats away the lubrication from the disk surface. This splotching can cover large areas and be very noticeable or it may be hard to discern. It may cover the entire surface of the disk, or it might only be seen in the head slots. If the rotational position of the disk has not been disturbed since its removal from storage, rotate it 1/2 the width of the head slot and look for a difference in coloration on the magnetic surfaces. I've come up with a solution (no pun intended) that will usually allow the data to be recovered if the disk isn't too badly damaged, like Don mentions (above). This procedure also applies to 3.5" disks. Examine the surface of the floppy before you put it in a drive for the first time, especially if it has been stored in a humid, warm area or if you don't know where it has been stored. Look for the splotching. If it is present, then be ready to immediately make a copy the first time you insert the floppy into a drive. You may only have this one chance. Apply some 91% (non-scented) or preferably 99% Isopropyl Alcohol to both sides of the disk in the head slot area. You want the alcohol to be absorbed onto the anti-friction liner of the floppy jacket, and you want enough of it so that it lasts through the reading/copying process. It may help to pucker the jacket to aid in the absorption of the fluid. Rotate the disk inside of the jacket enough that you are sure it is thoroughly wetted. Don't wet it so much that fluid is dripping off, though. If it is, shake off the excess, head slots away from you. The dripping and slinging of alcohol inside the disk drive mechanism is not good for the lubricated parts inside nor for the powered up electronics. INSURE EVERYTHING IS READY TO READ/COPY. Now, insert floppy and quickly perform the read/copy. I highly recommended that you have two floppy drives for doing this, unless you can read or copy the diskette in one pass. If not, you may have to wet the floppy more than once. If you get errors while reading, (S)kip or (I)gnore them if (R)etry doesn't work on the first couple of retries. The alcohol evaporates quickly, and you risk destroying areas of the disk that may have been readable had the alcohol remained. The alcohol accomplishes several things. It acts as a replacement for the missing lubrication, it helps scrub the fungus residue from the disk surface (which ends up on the jacket liner), it protects the heads from the abrasion of the molded areas and it keeps the heads flushed during the data recovery process. Due to the lubrication, the diskette will also rotate at the proper speed and timing/sync caused errors are eliminated. Alcohol is fairly inert in respect to the plastics used in many floppy drives. Also, if the drive used in this process is single sided, alcohol will not weaken the adhesive commonly used to attach the pressure pad. I've found that the best type of floppy storage for preventing this lubricant eating fungus, other than a proper storage environment, is an airtight container. Ziplock type bags work well. Bill whdawson