Dave's Hardware Tips.
If you suspect a hardware problem, get your machine checked immediately. Do not use it in the meantime and never test it with an important floppy disk - use a new one.
Don't switch the machine on or off with floppy disks in the drives unless you are booting from them. Get a mains spike protector and avoid using a ring main supplying devices that switch on & off or carry heavy loads. Even so, these gadgets won't prevent the dips - only an uninterruptible power supply (UPS) can do this. Try to avoid working late at night or during storms.
Use good quality branded floppy disks. These usually have a batch number or country of origin on them. Don't leave the disks in the drives for long periods. Recycle old disks frequently by reformatting them. Don't touch the surface of the disks. Keep them in jackets or boxes away from dust. Don't take the disk out of the drive while the disk drive light shows that it is being accessed.
Keep disks well away from magnetic fields from domestic or office equipment, magnets in telephones, hi-fi speakers or children's toys. Avoid extremes of humidity and temperature or dusty environments. If transient errors keep occurring, clean the drive sparingly with a non-abrasive head cleaner. If static electricity is a problem, earth yourself before working or get an antistatic mat.
Use the correct format of disk for the type of drive that you are using. A common problem with modern 3½" disks is the formatting of 720k disks in a high density drive as though they were 1.44 Megabyte disks. You can use 720k disks in a high density drive as long as they are formatted only to 720k. Similarly, formatting a high density disk (1.44Mbytes) in a low density (720k) drive is also risky. Data on such "cross-formatted" disks is seriously at risk. 1.44Mbyte disks have an extra hole in the corner of the disk opposite the "write-protect" hole; 720k disks do not.
The same problem also occurs with the older 5¼" disks. You should also avoid cross-formatting 360k and 1.2Mbyte disks. 360k disks have a hub ring; 1.2 Mbyte disks generally do not, although we recently saw some Japanese "photo" disks that do! 5¼" disks are also more vulnerable than modern 3½" disks. Avoid bending them and if you are sending them by post always put a stiffener in the parcel. Only write on the labels with a felt tip pen once they are stuck on these disks. Put the disks back in their protective jacket once they come out of the drive - lying them unprotected on the desk can scratch the disk surface.
The Amstrad PCW 3" 'flippy' disks are unusual. The PCW8256/8512 180k A: drive, is single-headed, so they can be used on both sides. However, the 720k B: drive of that machine and the A: drive of the PCW9512, are double headed so you can only use one side. Don't try to mix 180k and 720k formats or use the reverse side of a 720k 3" disk. On the Amstrad 8512 you can't write to a 180k disk in the 720k B: drive or to a 720k disk in the 180k A: drive. Don't try to copy a 720k B: disk onto a disk in A: - it won't.
After working with a 3" disk for a long period, lay it flat while it cools - the adhesive used in some of the cheaper disks melts and the hub may become off-centered. When you format a new disk for the PCW/PcW machines, reformat an old one, or copy a disk, use DISCKIT (or LocoScript 2, 3 or 4) to verify it afterwards. This checks that the disk is OK and may avoid problems later.
Last revised: 7th February 2003