Computer Science Introduction
What is a Computer
Computer???
Defenition
A Computer is an electronic devices operating under the control of instructions (software) stored in its own memory unit, that can accept data (input), manipulate data (process), and produce information (output) from the processing.
Generally, the term is used to describe a collection of devices that function together as a system.
Computer Systems
Monitor (output Device)
Speaker (Output Device)
Printer (Output Device)
Scanner (input Device)
Processing Unit
CD RW, Floopy (Storage Device)
Mouse ( Input Device)
Computer Systems
Hardware
Software
Brainware
PC
CRT Display
Keyboard
Mouse
“The Box”
CD-ROM Drive
Floppy Disk Drive
What does a computer do?
Computers can perform four general operations :
Input
Process
Output
Storage
Computer Generations
First Generation (1940 – 1956)
Used Vacuum Tubes for Circuitry
Magnetic drums for memory
Need a great deal of electricity
Used punch card and paper tape as input device
Print out as output
Machine Languange
Vacuum Tube
ENIAC I
ENIAC 2
Computer Generations
Second Generation (1956 -1963)
▪ Used Transistors
▪ Punch card as input
▪ Magnetic core technology for memory
▪ Print Out as output
▪ High level programming language
ILLIAC II
Computer Generations
Third Generation (1964 -1971)
Used IC & MSI
Used keyboard and monitor for users interacted with the computer
Used Operating system as interface
IBM
7090
3 computer’s component generations: VACUUM TUBE, TRANSISTOR and IC
Computer Generations
Fourth Generation (1971 – Presents)
▪ Microprocessor
▪ CPU and Memory to input output on a single chip
1
stPC: ALTAIR 8800
APPLE COMPUTER
IBM PC
Computer Generations
Fifth Generation ( Present and Beyond)
Artificial Intelligent
Voice recognition
Quantum computation and nano technology
Natural language
Classification of Computer Systems
According to Data Processing
Analog Computer
Digital Computer
Hybrid Computer
Classification of Computer Systems
According to size
▪ Micro Computer (PC)
▪ Mini Computer
▪ Mainframe
▪ Super Computer
▪ Laptop
▪ Palmtop
Software Classification
Exercises
1. Distinguish between hardware, software and brainware
2. Distinguish between application
software and system/utility software
3. Define high level languange and low level languange
4. Explain about classification of
computers according to size and data processing
5. Write about profession in IT
