Introduction to Computer and

Programming

CS-101

Lecture 1

Basics of Computers Definition

&Computer Generations

By :

Lecturer : Asad Abd Elrashid

College of Arts and Science

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Content

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Definition.

Computer Diagram.

Central Processing Unit(CPU).

Memory Unit (MU).

Definition

• A computer is an electronic machine that can

input, process, store and output a vast amount

of information at an extremely high speed.

(Or)

• A computer is an electronic device that

manipulates information, or data. It has the

ability to store, retrieve, and process data.

Computer Diagram

Central Processing Unit(CPU)

Arithmetic

and Logic Unit

Input Unit

Keyboard, mouse

Arithmetic and Logic

Unit

Output Unit

Printer, Monitor

Control Unit

Memory Unit

Main memory: ROM, RAM Secondary memory: hard disk

Input Unit and Output unit

• Input unit:-Used to enter the data or program

(instructions)

• Output unit:-Output the results or data

Central Processing Unit

CPU:-The data is processed in this unit.

1. Arithmetic and Logic Unit (ALU)

2. Control Unit (CU)

3.Memory Unit (MU)

Arithmetic and Logic Unit (ALU)

• An ALU can do arithmetic operations like

addition (+), subtraction (-), multiplication (*),

division (/).

• It also can do logic operations like true or

false, yes or no.

Control Unit (CU)

• The unit controls and co-ordinates all parts of

computer system.

Memory Unit (MU)

This is the storage device (used to store programs and data) .

Types of memory:

1. Main memory

2. Secondary memory

3. Cache memory

Main memory

Temporary memory because the data is erased.

When the power goes off. (in RAM)

It consists of RAM and ROM

RAM – Random access Memory

ROM – Read only Memory

Secondary memory Permanent memory or back up memory.

It stores a large amount of information for a

long time,

Speed is less than main memory.

Cache memory

High speed memory which placed between the

CPU and the main memory.

CPU

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Comprised of :

Control Unit

Retrieves and decodes program instructions

Coordinates activities of all other parts of

computer

Arithmetic & Logic Unit

Hardware optimized for high-speed numeric

calculation

Hardware designed for true/false, yes/no

decisions

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Input Unit

Output Unit

Secondary storage Device

Central Processing Unit

Memory Unit

Control Unit

Arithmetic/Logic Unit

Registers

CPU Operations

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Add

Subtract

Multiply

Divide

move data from location to location.

Control all processes.

Cont..

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Addresses – Each byte in memory is

identified by a unique number

– address Organized as follows:

– Information is stored in bits or binary digits.

– bit: smallest piece of memory. Has values

(0,off or false), OR (1 = on or true)

– byte: 8 consecutive bits. Bytes have addresses.

– Each cell has its own address that indicate the

location of stored data and instruction.

Main Memory

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Stores instructions and data that are to processed

by the computer.

• It is volatile.

Main memory is erased when program

terminates or computer is turned off by user

or by any mistake.

• Also called Random Access Memory (RAM)

Cont..

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Secondary Storage

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Mass storage device.

• Stores instructions and data between Stores

instructions and data between Sessions.

Non-volatile: data retained when program is not

running or computer turned off.

• Comes in a variety of media:

Magnetic: floppy disk, zip disk, hard disk

Optical: CD-ROM, USB – Flash drives, which is

connected to the USB port.

Cont..

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Hard disk

– Fast

– Fixed in the computer and not normally removed

Floppy disk

– Slow

– Easily shared with other computers

Compact disk

– Slower than hard disks

– Easily shared with other computers

– Can be read only or re-writable

Input Devices

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Devices that send data to the computer from

outside environment.

• Many devices can provide input:

– Keyboard, mouse, scanner, digital camera,

Microphone, disk drives(Hard disk), CD-

ROM,…, etc.

Cont..

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Output Devices

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Output is information sent from a computer

program to the outside world(User, customers,

company,… ,etc).

• The output is sent to an output device

• Many devices can be used for output:

– Monitor, printer, speakers, Floppy disk, zip

disk drives, Writable CD drives,… etc.

Generations of Computer

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The First Generation

of Computers (1948 — 1958)

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The main features of this generation are:

•Used vacuum tubes for circuitry.

•Used magnetic drums for memory.

•Used machine language to perform operations

•Able to solve one problem at a time.

•Output consisted of punched cards or papers.

Disadvantages of this generation

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• More costly to operate.

• Big in size.

• Generate lot of heat.

• Heavy air-conditioning is required.

• Less reliable.

• Consume very high power.

• Low storage capacity.

UNIVAC -1951

(Universal Automatic Computer)

UNIVAC -1951

•First fully electronic digital computer built in the U.S. •Created at the University of Pennsylvania •ENIAC weighed 30 tons contained 18,000 vacuum tubes •Cost a paltry $487,000

It is the Bendix G-15 General Purpose

Digital Computer, a First

Generation computer introduced in 1956.

SECOND GENERATION OF

COMPUTERS

The Second Generation of

Computers (1959 — 1967)

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Features of This Generation

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•Used Assembly language instead of binary

language.

•Later on used High Level Languages like

COBOL, FORTRAN BASIC and PL/I

•More reliable than previous generation.

•Smaller in size as compared to previous

generation.

•Produce less heat when compare with previous

generation.

Cont..

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•Less power consumption than previous

generation.

•High capacity of internal storage.

•Used magnetic core technology.

•Stored instructions in memory.

Disadvantages of this generation

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•Still require high air-conditioning.

•Input and output devices were very slow.

The Third Generation of

Computers (1968 — 1973)

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Cont..

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•First commercial operating system of real time

is introduced.

•Smaller in size when compared to first two

generations.

•Keyboards, Monitors were used

•Higher capacity internal storage.

•Operating system is used to control the

computer and its resources.

•Remote communication facilities made

possible.

Cont..

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• Multiprogramming facilities.

•Used High-Level Language (HLL), like RPG

and Pascal.

•Programs written for one computer were

compatible with others.

•High speed

•Small in size.

•Power consumption is low.

•Weight has decreased.

The Fourth Generation

of Computers (1974 — 1982)

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Features of This Generation

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•Contained entire CPU on a single silicon chip.

•Very much reliable as compared to all previous

generations.

•Magnetic disks became the primary means of

internal storage

•Large internal storage capacity.

•Single chip contains thousands of IC’s.

Cont..

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• The size became very small due to the use of

LSI (Large Scale Integrated) and VLSI (Very

Large Scale Integrated) circuits.

•Less expensive.

•Very fast when compared to all previous

generations.

The Fifth Generation

of Computers (1982 — Till now)

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Main features

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• Automatic programming, computational logic

and pattern recognition.

• Able to execute billions of instructions per

second.

• Easy and natural to use with high intelligence

and natural human input and output

mechanism.

• Reliable and efficient software development

by new languages.

• Improved functions and performance making

computers smaller, faster, lighter and flexible.

Cont..

• Less power consumption .

• High performance, lower cost and very compact.

• Computers based on artificial intelligence are

available.

• Portable note book computers introduced .

• Memory chips up to 1 GB, hard disk drives up to 180

GB and optical disks up to 27 GB are available (still

the capacity is increasing) .

Cont..

Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

challenge

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1- give an example of Two input device and two

out put device?

2- What is main memory function?

3- how the data stored on memory , draw simple

example?

4-What are Disadvantages of second generation

Thank you for your attention

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Lecturer : Aasd Abd Elrashid