Chapter 7

Actually this chapter explains various storage media and storage devices. Students discover how memory is different from storage. Floppy disks are introduced, and characteristics of a floppy disk, floppy disk drives, care of floppy disks, and high-capacity floppy disks are presented. Hard disks are explained, and students find out about characteristics of a hard disk, how a hard disk works, removable hard disks, hard disk controllers, RAID, and maintaining data on a hard disk. Compact discs, including CD-ROMs and DVD-ROMs, are described. Finally, students learn about tapes, PC Cards, and other types of storage such as smart cards, microfilm and microfiche.

Differentiate Between Storage And Memory

Memory, which is composed of one or more chips on the motherboard, is a temporary holding place for data and instructions during processing. The contents of volatile memory, such as RAM, are lost when the power to the computer is turned off. The contents of nonvolatile memory, such as ROM, are not lost when power is removed from the computer. Storage holds items such as data, instructions, and information for future use; that is, storage holds these items while they are not being processed. Storage is nonvolatile, which means the items in storage are retained even when power is removed from the computer. Compared to memory, the access time (the time it takes to locate a single item) for storage is slow.

Identify Various Types Of Storage Media And Storage Devices

A storage medium (media is the plural) is the physical material on which items are kept. A storage device is the computer hardware that records and retrieves items to and from a storage medium. Storage devices can function as sources of input and output. When storage devices transfer items from a storage medium into memory – a process called reading – they function as sources of input. When storage devices transfer items from memory to a storage medium – a process called writing – they function as sources of output. Types of storage media include floppy disks, hard disks, compact discs, tape, PC Cards, microfilm, and microfiche.

How A Floppy Disk Stores Data

A floppy disk is a portable, inexpensive storage medium that consists of a thin, circular, flexible plastic disk with a magnetic coating enclosed in a square-shaped plastic shell. A floppy disk drive (FDD) is a device that can read from and write on a floppy disk. When you insert a floppy disk into a floppy disk drive, a shutter on the disk’s plastic shell slides to the side to expose the disk’s recording surface. A floppy disk is a type of magnetic media because it uses magnetic patterns to store items. Data is stored in tracks and sectors. A track is a narrow recording band that forms a full circle on the surface of the disk. The disk’s storage locations consist of pie-shaped sections, which break the track into small arcs called sectors. For reading and writing purposes, sectors are grouped into clusters. A cluster consists of two to eight sectors and is the smallest unit of space used to store data. Formatting is the process of preparing a disk for reading and writing.

Describe How A Hard Disk Organizes Data

A hard disk, or hard disk drive, consists of several inflexible, circular platters that store items electronically. A platter in a hard disk is made of aluminum, glass, or ceramic and is coated with a material that allows items to be recorded magnetically on its surface. Each platter has two read/write heads, one for each side. Because of the stacked arrangement of the platters, the location of the read/write heads often is referred to by its cylinder, which is the location of a single track through all platters. Some computers improve hard disk access time by using a disk cache, which is a portion of memory that the processor uses to store frequently accessed items. A hard disk can be divided into separate areas, called partitions, each of which functions as if it were a separate hard disk drive.

Identify The Advantages Of Using An Internet Hard Drive

An Internet hard drive is a service on the Web that provides storage to computer users. People use Internet hard drives to:

• Eliminate the need to transport files when away from a desktop computer
• Instantaneously save large audio, video, and graphics files when surfing the Web
• Make audio files, video clips, or pictures available to family, friends, co-workers, and customers
• Immediately view time-critical data and images while away from a main office or location
• Store offsite backups of data