CompTIA A+ Certification

The most basic input device is the floppy disk drive. It was first developed in 1972 by IBM for their System 370 computers. These drives used 8-inch floppy disks. Other companies adapted the same basic design for their computers. The floppy disks came pre-formatted, and only worked on a given operating system or computer. This resulted in high-cost drives and reduced the ability to use floppies as a quick means of transporting files from one system to another. When IBM introduced the personal computer in 1981, it came standard with a 5.25-inch floppy disk drive.

The 5.25-inch floppy disk drive was replaced by a 3.5-inch version that was also called a stiffy disk drive. The 3.5-inch floppy disk drive uses the same technology as the 5.25-inch version drive but uses a 3.5-inch disk encased a plastic coat. The floppy disk drive is an inexpensive read/write removable media as the data stored on a floppy disk can be moved from one computer to another, provided both have similar floppy disk drives.

All floppy disk drives are connected to the motherboard's external data bus by a 34-lead ribbon cable, shown in Figure. This cable has a seven-wire twist in lines 10 through 16 to ensure that when two floppy disk drives are attached, the drive-select and motorenable signals on those wires can be inverted to select the primary active drive, designated the A drive by the BIOS.

The power connection for a floppy disk drive, is either the large, Molextype connector on the 5.25-inch floppy disk drive or the mini connector on the 3.5-inch floppy disk drive. Once you have physically installed a floppy disk drive, you must run the BIOS Setup program to adjust the proper CMOS settings for the drive type and capacity as well as the correct drive letter.

Floppy disk drives are one of the most fragile parts of a computer system. They are highly susceptible to failure because their internal components are directly exposed to the outside world. Often, there is only a small door or slot that separates the R/W heads from dust, grime, and cigarette smoke. Floppy disk drives are also often the victims of inverted disks, paper clips, and other foreign objects that can cause mechanical damage. They are however inexpensive and easy to replace. The only preventive maintenance required on them is to keep them clean. Cleaning kits are available in most computer and discount stores.

If a floppy disk drive does not work, the first thing you should suspect is the floppy disk. Make sure that the disk is not write protected or try another formatted disk. Beware not to test a drive by using a disk that contains important data as the disk drive may destroy any disks placed into it if the drive is faulty. If two or more disks are unreadable, then drive is probably faulty.