28.6 Step 6: Install the Floppy Disk Drive
Modern floppy disk drives have no user-configurable settings. All FDDs are set in hardware as B:. Whether the drive appears to the system as A: or B: depends on which cable position you attach the FDD to and how the BIOS is configured. Install the FDD, noting the following:
If the case has externally accessible 3.5" drive bay(s), use one of them for the floppy disk drive, saving the 5.25" bays for other purposes. If for some reason you must install the FDD in a 5.25" bay, you'll need to purchase an adapter for $5 or so.
A standard FDD cable has three connector positions, one on each end and one in the middle. Between the middle connector and one end connector, a portion of the cable is twisted. The two connectors separated by the twisted portion are used to connect drives. The other end connector attaches to the motherboard FDD interface. Attaching the FDD to the connector on the far side of the twist makes that FDD A:. Connecting it to the middle connector (before the twist) makes it B:. Some cables have five connectors, with two connectors (one header-pin and one edge-card) at each drive position. These dual connectors can be used interchangeably, depending on which fits the drive. The edge-card connector was used by 5.25" FDDs, which are obsolete, but many adapters that allow a 3.5" FDD to be installed in a 5.25" drive bay use the edge-card connector.
Most recent BIOSes support only one FDD, and have a BIOS setting that allows drives A: and B: to be swapped. This is important if the FDD cable supplied with your motherboard has only two connectors and no twist, as do some we have seen. In that situation, you can use the supplied cable to connect the drive, but make sure to use BIOS Setup to swap A: and B: so that the installed drive appears as A:.
Once you have determined where to install the drive and which connector you will use, slide the drive into the bay. Some drives and cases require that the FDD be installed from the front of the case, and others from the back. FDDs are inexpensive devices, and manufacturers don't spend much money on amenities such as shrouded connectors, so it's often easier to connect the data and power cables to the drive before you slide it into the bay.
Although power cables are keyed, it can be difficult to line up the connection after the drive is installed. If the power cable is too short to allow connecting it to the drive while the drive is outside the case, you will have to connect it after the drive is installed. Depending on where the drive is mounted, it may be difficult to see the connector with the drive in place. If that's true for your system, connect the power cable to the drive temporarily to determine how it should be oriented, e.g., "red wire toward the data cable."