This document provides an overview of computer hardware by discussing computer generations, classification of computer systems, computer system concepts, and computer peripherals. It describes the evolution of computers from early generations that used vacuum tubes to modern generations that use microprocessors. It classifies systems as microcomputers, midrange, and mainframe and discusses their characteristics. It also outlines the basic components and functions of a computer system including the CPU, memory, storage, and multiple processor designs. Finally, it lists common input and output technologies for computers.

1. Overview of Computer Hardware
Computer Generations
Classification of Computer System
Computer System Concept
Computer Peripherals

2. Computer 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.

3. Computer 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.

4. Computer 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.

5. Computer 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.

6. Classification of Computer System
 Microcomputer System
 Midrange Computer System
 Mainframe Computer System

7. Classification 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.

8. Classification of Computer System
 Network computer

9. Classification 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.

10. Classification of Computer System
 IBM Netfinity

11. Classification 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
corporation and government agencies or with complex
computational problems.
– Used as superserver for large client/networks and high
volume internet website.
– Supercomputer

12. Classification of Computer System
 IBM S/

13. Classification of Computer System
 Supercomputer IBM RS/ SP

14. Computer System Concept
 Computer is a system of hardware devices
organized according to the following system
functions
 Input
 Processing
 Control
 Output
 Storage

15. Computer System Concept

16. Computer System Concept
 Central Processing Unit (CPU)
– most important hardware component of a
computer system
– divided into two subunits
 Arithmetic-Logic Unit or ALU
 Control Unit

17. Computer System Concept
 Intel Pentium II microprocessor

18. Computer System Concept
 Primary Storage
– commonly called main memory
– holds data and program instruction between
processing step
– most computer memory consists of
microelectronic semiconductor memory chips
known as
 RAM ( Random Access Memory )
 ROM ( Read Only Memory )

19. Computer 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
computer system.

20. Computer 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.

21. Computer 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.

22. Computer Peripherals
 Input Technologies
– keyboard
– pointing device. E.g. electronic mouse, track
ball, pointing stick, touch pad, touch screen
– pen-based computing
– voice recognition and response
– optical scanning
– magnetic stripe
– digital cameras

23. Computer Peripherals
 Output Technologies
– Video output
 Video monitor
 Liquid Crystal Display (LCD)
– Printed output
 Inkjet printer
 Laser printer

24. Computer Peripherals
 Pen-based tablet recognizes handwriting on its
display screen