Upgrading and Repairing PCs

Floppy Drive Installation Procedures

A floppy drive is one of the simplest types of drives to install. In most cases, installing a floppy disk drive is a matter of attaching the drive to the computer chassis or case and then plugging the power and signal cables into the drive. Some type of brackets and screws are usually required to attach the drive to the chassis; however, some chassis are designed to accept the drive with no brackets at all. Any brackets, if necessary, are normally included with the chassis or case itself. Several companies listed in the Vendor List on the DVD specialize in cases, cables, brackets, screw hardware, and other items useful in assembling systems or installing drives.

Note Because floppy disk drives are generally installed into the same half-height bays as hard disk drives, the physical mounting of the drive in the computer case is the same for both units. See the section "Hard Disk Installation Procedures," earlier in this chapter, for more information on the process.

When you connect the drive, make sure the power cable is installed properly. The cable is usually keyed so you can't plug it in backward, but the keying can be defeated by somebody forcing the connection. If that is done, the drive will be fried the instant the power is turned on.

Next, install the interface cable. A floppy interface cable is a 34-pin cable that typically has a twist in it. What I mean is that pins 10–16 are twisted around before they reach the last (A:) drive connector. Normally, the A: drive must be plugged in after this twist; any drive plugged into a connector before the twist is seen by the system as drive B:. The twist reverses the drive select and motor enable signals, letting A: and B: drives coexist without rejumpering. This is similar to the way Cable Select works for ATA/IDE drives. Because of this, all floppy drives are jumpered the same way, in the second Drive Select (DS) position.

Older drives used to require various jumpers to be set to enable the drive to work properly. The two most common jumpers were the Drive Select jumper and the Disk Change (DC) jumper. If you encounter an older drive with these jumpers, you should follow a few simple rules. The DS jumper typically has two positions, labeled 0 and 1—or in some cases, 1 and 2. In all PC installations, the DS jumper should be set on the second position, no matter what it is numbered. This enables the drive on the cable before the twist to function as drive B: and the drive at the end of the cable after the twist to function as drive A:. The DC jumper setting is normally an on or off setting. For PC use, if the drive has a DC jumper, it must be set on or enabled. This enables the PC to detect when you have changed disks in the drive. For more information on floppy drives and interfacing, see Chapter 11.

The interface cable is usually keyed to prevent backward installation. If no key exists in this cable, use the colored wire in the cable as a guide to the position of pin 1. Normally, pin 1 is oriented closest to the power connector, which is the same as other drives. If the drive LED stays on continuously when you power up the system or when the system is running, that is a sure sign you have the floppy cable on backward either at the drive end or at the controller (motherboard) end.