Floppy disk handling and storage. David H. Ahl.
Floppy Disk Handling and Storage
If you have ever wiped out a floppy disk but not known the reason why, you have lots of company. A few months ago, after a spate of unfortunate disk disasters on two trips, we decided to look into the problem in depth. Could it be the airport weapons detectors? Were the disks deteriorating from age? Was it high temperature or humidity?
We wrote to ten manufacturers of floppy disks with a list of questions about "unusual' situations and also asked their advice on everyday disk handling. Only two manufacturers replied--Maxell and Verbatim--which perhaps is an indication that most manufacturers would rather sell you new disks than tell you how to keep the old ones from wearing out.
We'd like to thank Ted Ozawa and David Berry of Maxell and Erica Baccus of Verbatim for their help in putting together this article.
Disk Surface. On a single sided disk, the recording surface is on the lower side, i.e., opposite from the label. Thus removing it from the drive and laying it on a dusty desk is not recommended. Just about anything is large enough to interrupt the contact between the head and disk surface and result in a loss of data (see Figure 1). When the disk is removed from the drive it should always be stored in its protective envelope. Don't ever touch the surface of the disk; fingerprints are bad news.
Disk Cleaning. In general, it can't be done. Moreover, many solvents such as alcohol, thinner, and freon will remove the oxide from the disk surface. Keep your heads clean with one of the commercial cleaning kits, and your disks should remain clean.
Bending and Squeezing. Don't bend or fold a disk. Placing heavy objects on disks or jamming them together in a storage box will crush the jacket edges and cause them to spin unevenly, thus making reading and writing erratic.
Labels. If possible, the label should be written on before placing it on the disk. If, however, you must write on a label that has already been applied, use only a felt or nylon tip pen, never a ballpoint pen or pencil. Never use an eraser on a disk label, and use peelable labels which don't leave a residue. Peel off the old label when putting a enw one on; don't apply labels in layers.
Jacket Care. Do not use a paper clip, rubber band, or any other fastener on a disk jacket or envelope. Instead, put the disk and protective envelope in a plastic or paper envelope and fasten that to whatever you must.
Disk Storage. Disks not being used should be stored upright in a dustproof container. If they are stored on top of one another, there is a tendency for the jackets to become warped. Unlike cassette tapes, if a disk is in long-term storage, it is not necessary to give it a spin every once in a while.
Shelf Life. As long as a disk is stored in the proper temperature range (50~F to 125~F) and humidity range (8% to 8%), the shelf life is 30 years (according to Verbatim) or "practically forever' (according to Maxell). As we all know, in personal computing, 30 years is practically forever. Magnetic tapes are susceptible to the oxide flaking off after a period of time; disks do not have this problem, and the magnetic life is virtually infinite.
Service Life. In normal use with a drive that is in good repair, a disk will provide three to ten million passes. A data disk that is constantly being written and erased will have considerably more head contact than, say a game disk that is just loaded once per session. Nevertheless, it is difficult to conceive of a disk being subject to anything like three million passes.
Operating Environment. Like the storage environment, the operating temperature range should be 50~F to 125~F with relative humidity between 20% and 80%. Obviously, excessive heat or sunlight are to be avoided.
Magnetic Fields. Since the data on a disk are stored in minute magnetic regions, the information can be altered or completely eliminated if the disk is exposed to a magnetic field. Permanent magnets such as those on typing guides or those used to hold memos on the side of a file cabinet should be kept at least one foot away from disks. Permanent magnets are also found in loudspeakers. Although it is not likely that a speaker in a housing will cause problems with a disk, it is best not to tempt fate by putting disks on top of a speaker.
However, any transformer or motor generates a magnetic field. Very small motors such as those used in disk drives, cassette recorders, or printers are not a problem, however, larger motors such as those found in air conditioners can be if a disk is too close. Also, disks should be kept away from external power supply transformers such as those used with Atari computers. Likewise, disks should be kept away from the ballasts in fluorescent desk lights and the transformers in the bases of high intensity lamps.
Airport Metal Detectors. The walk through weapons detectors used in airports generate a slight magnetic field (about 5 oersteds) but not nearly enough to affect a disk (50 or more oersteds). The detectors used to examine carry-on baggage are X-ray detectors and have no detectable magnetic effects.
Sending a Disk in the Mail. An old wives tale has it that disks should be wrapped in foil when they are mailed. Not so; aluminum foil provides no magnetic protection and it isn't necessary anyway. Much more important is to keep the disk from being bent or crushed. For this, a stiff piece of cardboard or hard foam plastic is best. Commercial mailers known as Floppy Armor provide excellent protection.
If you follow these dos and don'ts, and clean your drives regularly, your disks should give you a lifetime of service.
Photo: Figure 1.