Download Generations of Computers

Chapter 1
Introduction
What is a Computer?

Electronic device that takes in data and
instructions (input), works with the data
(processing) and Put out the information
(output)
Computer Components

Hardware
Input devices
 CPU
 Storage devices
 Output devices
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
Software
System software
 Programs

Generations of Computers

First generation
vacuum tube-based
electronic computer.
 Use machine language.
 Very large and slow.

Generations of Computers

second generation
transistor-based
electronic computer.
 Reduction in size and
cost.
 More faster
 Use assembly language.

Generations of Computers

Third generation
integrated circuits replaced several individually wired
transistors.
 Faster and smaller in size.
 Use programming languages such as:


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C
Fortran
Basic
Cobol
Generations of Computers

Forth generation
Use large-scale integration
technology.
 the need to speed up the software
development process
 Use friendly programming
languages.

Generations of Computers

Fifth generation
Very Large-Scale Integration
technology (VLSI)..
 make use of parallel processing
 Artificial intelligence
 Prolog

Range of Computers

Embedded Systems
chips in washing
machines,
 laser printers
 hand calculators.

Range of Computers

Microcomputers
personal computers
 Multitasking
 Networking
 PRICE: between $700
- $2000

Range of Computers

Minicomputers
These perform multi-tasking
and allow many terminals to be
connected to their services.
 Business, to process large
amount of data.
 PRICE: between $15,000 $150,000

Mainframe Computers
Mainframe computers are
large general purpose
computers.
 Large databases.
 government departments
and the airline industry

Supercomputers


very fast and have
multiple processors.
developed for scientific
applications usually
involving complex
arithmetic and
mathematical operations.
Basic Computer System

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ALU
Control Unit
Registers
internal bus.
Registers



Accumulators - serve the purpose of holding
data used in calculations
Instruction Pointer - sometimes referred to as
the program counter, the pointer is responsible
for retaining the memory address of the next
instruction to be executed
Address Registers - are used for storing the
memory location of data or instructions to be
used by a program.
Control Unit




Decoding the instruction
sequencing the reading and writing of data
controlling the sequence in which instructions
are executed.
controlling the operations performed by the
ALU
External Buses
Fetch and Execute
Input devices

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Keyboard
Mouse
Joystick
Light pin
……