Chapter 4

Storing Information in a Computer

Peter Norton’s Introduction to Computers

Learning Objectives:• List four common types of storage devices.

• Name three common uses of floppy disks.

• Name the four data disk areas on floppy and hard disks.

• List three ways tape drives differ from disk drives.

• Identify four types of optical storage devices.

• Name and describe the four main disk drive interface standards.

Storage Media - the physical components or materials on which data is stored.

Storage Devices - the hardware components that write data to, and read it from, storage media.

Types of Storage:

• Magnetic

• Optical

Magnetic: the bitsare written and read

using magnetism.

Optical: the bitsare read

using light.

Magnetic Storage Devices:

• Diskettes

• Hard disks

• Removable hard disks

• Magnetic tape

Tape drive

Floppy drive

Hard drive

Optical Storage Devices:

• Compact Disk Read-Only Memory

(CD-ROM)

• Write Once, Read Many (WORM)

• Phase-Change Rewritable disks

• Magneto-optical disks

CD-ROM

Factors that Affect Drive Performance:

• Average Access Time

• Data-transfer Rate

Average Access Time - the average time it takes a read/write head to move from one place on the recording medium to any other place on the medium.

Data-transfer Rate - a measure of how long it takes the device to read or write a given amount of data.

Hard drive RAM

Head

Formatting - the process of mapping a diskette by dividing it into Tracks and Sectors.

Tracks - a set of magnetic concentric circles.

Sector - a pie-like slice of disk.

Four Areas of a Disk:

• The boot record

• The file-allocation table (FAT)

• The root folder or directory

• The data area

Drive-Interface Standards:

• Integrated Drive Electronics (IDE)

• Enhanced Small Device Interface (ESDI)

• Small Computer System Interface (SCSI)

Learning Objectives:Chapter 4 Review

• List four common types of storage devices.

• Name three common uses of floppy disks.

• Name the four data disk areas on floppy and hard disks.

• List three ways tape drives differ from disk drives.

• Identify four types of optical storage devices.

• Name and describe the four main disk drive interface standards.