Overview of Computer HardwareOverview of Computer Hardware

Computer GenerationsClassification of Computer SystemComputer System Concept Computer Peripherals

Computer GenerationsComputer Generations

First Generation Computer– Early 1950s.– Used thousands of vacuum tubes for processing

and memory switching.– Used magnetic drums or tape secondary storage– Used paper tape as Input and Output media.– Has main memory of only a few thousand

character.

Computer GenerationsComputer Generations

Second Generation Computer– Late 1960s.– Used transistors and other solid-state

semiconductor devices.– Main memory capacities of less than 100

kilobytes.– Magnetic disk packs and magnetic tape were

used as I/O and secondary storage medium.

Computer GenerationsComputer Generations

Third Generation Computers– 1970s– Used integrated circuits.– Main memory capacities increased to several

megabytes.– Possible used of operating system program.– Wide spread use of small computer called

microcomputer.

Computer GenerationsComputer Generations

Fourth Generation Computers– 1980s and 1990s– Used LSI and VLSI technologies.– Used microprocessor.– Magnetic core memory is replaced by memory chips.– Main memory capacity ranging from a few megabytes

to several gigabytes.

Fifth Generation Computer– as we enter 21st century.

Classification of Computer SystemClassification of Computer System

Microcomputer SystemMidrange Computer SystemMainframe Computer System

Classification of Computer SystemClassification of Computer System

Microcomputer System– Usually called personal computer or PC.– Variety of size and purpose, e.g. handheld, notebook,

desktop.– Workstation computers– Network servers– Personal Digital Assistants (PDA)– Multimedial PC– Network Computer.

Classification of Computer SystemClassification of Computer System

Network computer

Classification of Computer SystemClassification of Computer System

Midrange Computer System– Multi-user system that can manage networks of PCs and

terminals.– Includes minicomputers and high-end network servers.– Not as powerful as mainframe computers but less costly

to buy, operate and maintain than mainframe system.– Serves as industrial process-control and manufacturing

plant computers.

– Popular as network server.

Classification of Computer SystemClassification of Computer System

IBM Netfinity 7000

Classification of Computer SystemClassification of Computer System

Mainframe Computer System– Large, fast and powerful computer.– Can process hundreds of million instruction per second.– Has large primary storage capacity.– Handle information processing needs of major corporatio

n and government agencies or with complex computational problems.

– Used as superserver for large client/networks and high volume internet website.

– Supercomputer

Classification of Computer SystemClassification of Computer System

IBM S/390

Classification of Computer SystemClassification of Computer System

Supercomputer IBM RS/6000 SP

Computer System ConceptComputer System Concept

Computer is a system of hardware devices organized according to the following system functions

Input Processing Control Output Storage

Computer System ConceptComputer System Concept

Computer System ConceptComputer System Concept

Central Processing Unit (CPU)– most important hardware component of a comp

uter system– divided into two subunits

Arithmetic-Logic Unit or ALU Control Unit

Computer System ConceptComputer System Concept

Intel Pentium II microprocessor

Computer System ConceptComputer System Concept

Primary Storage– commonly called main memory– holds data and program instruction between pro

cessing step– most computer memory consists of microelectr

onic semiconductor memory chips known as RAM ( Random Access Memory ) ROM ( Read Only Memory )

Computer System ConceptComputer System Concept

Secondary Storage– devices like magnetic disks, optical disk ,etc.– has larger storage capacity than computer main

memory– play supporting role to primary storage and co

mputer system.

Computer System ConceptComputer System Concept

Multiple Processor Designs.– Support Processor

relies on specialized microprocessors to help the main CPU perform a variety of functions.

E.g. arithmetic co-processor, video display controller, etc.

– Coupled Processor uses multiple CPU or main microprocessor. Executing more than one instruction at the same time.

Computer System ConceptComputer System Concept

Multiple Processor Designs (continued)– Parallel Processor

uses group of instruction processor to execute several program instruction in parallel.

hundreds or thousands of processor are organized in network.

– RISC Processor Reduced Instruction Set Computer uses smaller number of basic machine instruction. Required more complex software.

Computer PeripheralsComputer Peripherals

Input Technologies– keyboard– pointing device. E.g. electronic mouse, track ball, po

inting stick, touch pad, touch screen– pen-based computing– voice recognition and response– optical scanning– magnetic stripe– digital cameras

Computer PeripheralsComputer Peripherals

Output Technologies– Video output

Video monitor Liquid Crystal Display (LCD)

– Printed output Inkjet printer Laser printer

Computer PeripheralsComputer Peripherals

Pen-based tablet recognizes handwriting on its display screen