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.