WINDOWSPart 4 – Components of

Computers

A World of Computers• Computer Literacy

– Knowledge and understanding of computers and their uses

– Computers are everywhere

Computer Applications in Society• How are computers used in society?

Education Finance Government Health Care Science Publishing Travel Manufacturing

What Is a Computer?• Computer – an electronic device, operating

under the control of instructions stored in its own memory, that can:–process the data according to specified

rules (processor)–accept data (input)–produce results

(output)–store the results

(storage) for future use

What Does a Computer Do?• The four basic

operations compromise the Information Processing Cycle

Processor

• Processor – interprets and carries out the basic instructions that operate a computer–Called Central Processing Unit (CPU)–The brains of the computer–Measured in hertz

• Control Unit – interprets the instructions

• Arithmetic/Logic Unit – performs the logical and arithmetic processes

Units of Speed(characters processed per second)

• Hertz – approximately 1 character• Kilohertz – approximately 1,000 characters• Megahertz – approximately 1,000,000

characters (1 million)• Gigahertz – approximately 1,000,000,000

characters (1 billion)• Terahertz – approximately 1,000,000,000,000

characters (1 trillion)

Memory• Memory – consists of electronic

components that store data, instructions, and information, as needed by the processor– Measured in bytes

– RAM – Random Access Memory• Holds the instructions, programs, information

you input• Will be lost if not saved (Measured in bytes)

– ROM – Read Only Memory• Can be read but not modified (system files)

Units of Memory

• Byte – approximately 1 character• Kilobyte – approximately 1,000 characters• Megabyte – approximately 1,000,000

characters (1 million)• Gigabyte – approximately 1,000,000,000

characters (1 billion)• Terabyte – approximately

1,000,000,000,000 characters (1 trillion)

Storage Devices

• Used to store instructions, data, and information when they are not being used in memory

Magnetic Disks

• Magnetic disks use magnetic particles to store items on a disk’s surface– Floppy disks– Zip disks– Hard disks

Optical Discs• Optical discs

– CD-ROM– CD-R– CD-RW– DVD-ROM– DVD-R– DVD+R– DVD-RW– DVD+RW– DVD+RAM

• Tape

Miniature MobileStorage• Miniature mobile storage

media

Flash Drives

• Small, removable storage devices that range from 64 MB to 64 GB

• Integrated with a USB interface

System Unit

• The processor, memory & storage devices are housed in a box-like case called the system unit

Input Devices• Any hardware component that allows you

to enter data, programs, commands, and user responses into a computer

• Input Device Examples:– Keyboard– Mouse– Web Cam– Scanner– Camera

Output Devices• Output devices make the information

resulting from processing available for use• Output Device Examples

– Printers (dpi/ppm)• Impact (dot matrix)• Photo

(inkjet/bubble jet) • Nonimpact (laser)

– Display Devices• CRT• LCD

Components of a Computer