Floppy drives are the slots on the front of your computer that you insert disks into, copy files to, and install programs from. Old ones are 5¼" wide; these drives are big and ugly. They accept the big 5¼" disks that can't hold very much data. Today, we laugh at a computer that still has one of these things. Almost all of us now have 3½" drives. These drives accept 3½" disks. These diskettes come in different densities. The old ones are single-sided and only hold 720 KB of data. The standard disks of today are called high-density. They usually hold 1.44 MB of data. The newest disks are called extended-capacity and they hold 2.88 MB.

Before a floppy diskette can be used, it must be formatted. This prepares the disk so that the drive can use it. To do this, type FORMAT A: at the DOS prompt (C:),. When Windows asks for a! label, it wants to know what you want to call the disk.

Notes: You can't use a high-density disk in a low-density drive. Also, when formatting, make sure you type A:. Do not type any other drive, especially C:, otherwise you're in for trouble. Floppies are almost always A:. Also, disks can go bad. If a particular diskette has many errors, trash it.

Installation

1. Choose which drive bay in which you want to install the drive and remove the face plate from that bay. Save the face plate for future use. If you are going to install a 3½" drive into a 5¼" bay, you'll have to use a special front panel to adapt it. This panel usually comes with a new floppy drive.

    

2. Fit the drive into the bay without connecting anything. Just make sure it fits.

3. Connect the ribbon cable and the power supply to the drive. If you just removed a floppy drive, just use the same connections. If not, study the available connectors. You should have a ribbon cable with a twist on one end. The end without the twist is attached to the floppy controller. Then, attach the connector after the twist to floppy drive A:. (If you have only one floppy drive, it is called Drive A:.) Yo! u may have two available connectors after the twist. Use the one that fits your drive. One is for 5.25" drives, the other is for 3.5" drives.

    

4. If you are using brackets to hold the drive in place, secure them now. You may need to temporarily disconnect the cables. Once in, tighten the drive in place. Double-check the connections.

    

5. Now put everything back together. Turn your computer on.

    

6. Now you have to tell the computer that it has another drive. This involves updating the BIOS. Boot the computer and enter setup. This is done by pressing F1, CTRL-ALT-ESC, or some other combination. Your computer will tell you what keys to hit right after you turn it on. After entering setup, go to the Standard Setup, usually the first menu option. Your main floppy drive is A:. Any second floppy drive is labeled B:. Using the appropriate keys, activate your new drive. Lastly, under another menu option, you mig! ht need to make sure your BIOS drive swapping is turned off. This feature, through BIOS, reverses the order of your floppy drive letters so that their location next to the ribbon twist does not matter. But, if you installed a drive after the twist, and this option is enabled, your Drive A: will not work.

   To deactivate a drive you have removed, follow the same instructions, but change the status of the drive to "None" or "Not installed." If you have removed the primary floppy drive, you'll need to change the Boot Options to "C: Only."

    

7. When you are done adjusting BIOS, save the new setup and exit. Your system should now restart and your drive will be activated. You can test it in the Explorer or File Manager by checking a diskette.

Internal Workings

The inside of a standard floppy drive has many similarities to the inside of a hard drive. It has the same basic parts.

Most floppy drives have two read/write heads, meaning that it is double-sided. These heads are used to read and write data to the diskette. Like a hard drive, the head mechanism is moved by the head actuator. It is a stepper motor design, much like the old hard drives. This small motor moves the heads in and out, giving them the ability to position themselves over any track on the disk. The heads use a recording method known as tunnel erasure. Basically, this recording method is a way to keep each track of data. As the head writes the data to a track, the tunnel erase heads come along and erase the outer edges of the track, thereby creating a sharp-edged track, very distinct from the others. This keeps the data on one track from being confused with data from another track, thereby eliminating problems.

The heads are spring loaded, therefore, they ar! e physically contacting the disk while they are reading and writing. The drive spins the disk at about 300 RPM; therefore, this contact is not a problem to the data because friction is minimal. Some diskette makers coat the disk with Teflon, further reducing friction between the heads and the disk. Eventually, a build-up of Teflon will form on the heads, requiring you to clean them.

The spindle motor spins the disk. As said before, it spins the disk at 300 RPM. On old 5.25" drives, the disk is spinned at 360 RPM. Older drives had the spindle motor attached to a belt system that spinned the disks. These were not very reliable, and the RPM was not constant. Today's drives use a direct-drive system with no belts. This system has automatic torque compensation so that sticky disks are spinned with greater force than a slippery one, thereby maintaining a constant 300 RPM with all disks.

The newer drives have this automatic ability, while older ones require periodic adjusting! . This is done by using the strobe marks that are on the motor. You run the drive in fluorescent light and adjust the RPM until the marks look still, just like a car rim or wagon wheel when turned fast enough.

Underneath the drive, you have the logic board. Like the hard drive, it serves to control the internal parts of the drive and serves as an interface between these parts and the floppy drive controller. All floppy drives use the SA-400 interface. For this reason, any floppy drive will work with any computer, right out of the box.

The front of the drive is called the faceplate. This is the part of the drive which is visible from the front of the case. These faceplates come in several sizes and colors. Some faceplates are larger than the rest of the drive, requiring you to install the drive from the front, a habit you'll probably form anyway.

The connectors are on the back of the drive. There are two: the power connector and the ribbon cable connector. Their only! difference is that the large 5.25" drives use a larger power plug, similar to the type used in a hard drive. If you are installing a 3.5" into an older case, you might not have the small-type connector available. In this case, you will have to buy an adapter to convert the large plug into the small type. The 3.5" drives use a smaller plug. All floppy drives use the same 34-pin data cable.

Occasionally, you might find a floppy drive that has weird connections. Some drives have one 40-pin connector that carries both the power and the data. Others use one 34-pin cable that carries both. However, these drive are rather rare.

Configuration

Floppy drives are bought off the shelf already configured for your computer. But sometimes, if you are installing a used drive, you may need to reconfigure it.

Drive Select

All floppy drives are attached in a daisy chain arrangement within the PC. This means that there is one cable leading from drive to drive. Therefore, like a SCSI daisy chain, each drive must have an ID number. Some older drives allow four choices IDs. However, modern PC floppy controllers can only support two floppy drives in a chain. The drive you want to be Drive A: is set to the first drive select position. Drive B: is set to the second position. The jumper that controls this is usually called the DS jumper, and the options are labeled DS0 and DS1. The numbers themselves may vary from drive to drive.

When installing floppy drives, for the most part, you don't have to worry about this. Most drives are factory set to DS2, or Drive B: position. In order to ! use the drive as a drive A:, you use a floppy ribbon cable that tricks the computer into using the drive as A:. This is done with the use of a special twist in the cable that electrically changes the DS configuration of the drive after the twist. This twist, then, causes the controller to think the drive configured as B: is really configured as A:. For this reason, during installation of a floppy drive, always make sure your Drive A: is located AFTER the twist on the floppy ribbon cable. If you are trying to use a non-standard floppy cable without a twist, you'll have to change the DS jumper to DS1, or the Drive A: setting.

Termination

Like a SCSI chain, a floppy drive daisy chain must be terminated at one end.

Older 5¼" drives used a terminating resistor in the drive itself that is plugged into the end of the cable. This terminator absorbs all signals, preventing reflections and echoes from going back down the line and disturb! ing new oncoming data. When connecting two of these 5¼" drives on the same chain, the drive at the end of the cable has a terminating resistor installed. Then, the resistors in the other drives on the chain have to be removed.

With 3½" drives, the termination is automatic. All 3½" drives have a pre-installed, non-configurable terminating resistor. With 3½" drives, each drive shares the role of termination. If you have only one drive on the chain, it terminates itself.

When installing 5¼" and 3½" drives on the same chain, you should remove the termination on the 5¼" unless it is at the end of the ribbon cable.

The terminating resistor looks like a 16-pin memory DIP chip. It is almost always a different color than the other chips on the drive. Sometimes, the chip is soldered on. In this case, you must either enable or disable the resistor with a jumper. The best way to ID your resistor is to look at the drive's manual.

As far as termination on the controller end, i! t is built in to the controller.

Media Sensor

3½" 1.44 MB or 2.88 MB drives are equipped with a Media Sensor (MS) jumper. This jumper enables or disables the media sensor in these drives. On many of these drives, it is factory set to be enabled. Sometimes it is even stuck in enabled mode. In short, this media sensor gives the drive the ability to sense what type of disk is inserted and thus adapt the read/write heads to work accordingly.