Disk Drives

We have identified the need for an external storage media and made a comparison between two popular forms of storage media—the hard disk and the floppy disk. However, the microprocessor does not perform the task of writing on or reading from this media. A device specially designed to perform these functions is the disk drive.

Data is fed into the PC and written on the hard disk or the diskette by the disk drive. When the data is to be processed, it has to be read from the disk before processing actually takes place. The disk drive also performs this function of reading the data. Since the disk drive performs both the tasks of writing and reading the data, in other words, the input and output functions, it is referred to as an \nput-output device.

A simple analogy of how a disk drive works is the cassette tape recorder. It encodes music and stores it on a cassette tape as a series of signals. It also reads the stored signals on the cassette tape and converts them back to music. The cassette player records as well as plays back the music. Therefore, it performs both reading and writing. A disk drive works in much the same way, reading and writing whenever required.

The disk drive is contained within the system unit. The drive for a diskette is called a diskette drive while the drive for a hard disk is called the hard disk drive.

It is important to differentiate between the storage media and storage devices. While the diskette and the hard disk on which data is stored are the storage media, the disk drives are the devices that do the reading and writing. Going back to the analogy of the cassette tape recorder mentioned earlier, the cassette tape would be called the storage medium while the cassette player is the storage device.