Q: Describe one type of secondary devices in detail.

A:

For hard disks:

Hard disks save files by altering the magnetic charges of the disk's surface to represent 1s and 0s. Hard disks retrieve data and program by reading these charges from the magnetic disks .Characters are represented by positive and negative charges using the ASCIL, EBCDIC, or Unicode binary codes. Density refers to how tightly these charges can be packed next to one another on the disk. Hard disks use rigid metallic platters that are stacked one on top of another. Hard disks store and organize files using tracks, sectors, and cylinders. Tracks are rings of concentric circles without visible grooves. Each track is divided into invisible wedge-shaped sections called sectors. A cylinder runs through each track of a stack of platters. Cylinders are necessary to differentiate files stored on the same track and sector of different platters. When a hard disk is formatted, tracks, sectors, and cylinders are assigned.

Hard disks are sensitive instruments. Their read/write heads ride on a cushion of air about 0.000001 inch thick. It is so thin that a smoke particle,fingerprint, dust, or human hair could cause what is known as a head crash. makes contact with the hard disk's surface or with particles on its surface. A head crash occurs when a read/write head makes contact with the hard disk's surface or with particles on its surface. A head crash is a disaster for a hard disk. The disk surface is scratched and some or all of the data is destroyed. At one time, head crashes were commonplace. Now, fortunately, they are rare. And there are two basic types of hard disks: internal and external.