Introduction to Computer Systems

Computers in Our World 

Computers are everywhere

We can find them in pretty unlikely places

• Family car
• Home appliances
• Alarm clock
• Market

The Computer Defined

Black Box

Problem Solver

An Electronic device that converts data into information which is useful to people

Anatomy of a Computer

Every computer has four basic parts, or units:

• an input unit such as the keyboard, that feeds information into the computer
• a central processing unit (CPU) that performs the various tasks of the computer
• an output unit , such as a monitor , that displays the results;
• a memory that stores information and instructions.

Computer  vs  Human

• Input  –  Five senses
• Central Processing Unit (CPU) – brain
• Output  –  Body Parts
• Memory  –  Human memory
• Hardware

Physical components

• Software

Programs for operations and problem solving

Modern Computers

Modern computers are digital

• Word “by the numbers”
• Break all types of information into tiny units
• Use numbers to represent information
• Two digits combine to make data (0, 1)

 

History of Computers

Older computers were analog

• represent data as variable points along a continuous spectrum of values.
• More flexible but not necessarily more precise and reliable

Slide Rule

Older computers were analog

A more manageable type — the old-fashioned slide rule

ABACUS

• 3000 BC: The first calculating device ABACUS was invented in Egypt .
• The abacus is still in use in some countries especially China, Japan
• Operations

Addition, subtraction, division and multiplication

Extract square root and cube root

• User has to memorize certain rules

Pascaline

• 1642: A Frenchman Blaise Pascal introduced the first mechanical calculating device.
• Series of wheels with teeth which could be turned using hands
• Used to handle 999,999.99
• Perform both addition and subtraction.

Difference Engine

• 1833: Charles Babbage

Professor of Mathematics

Cambridge University

With Assistance of Lady Augusta Ada Lovelace

• developed a machine that could store information, calculate numbers and solve algebraic expression.

Punched Card

• 1890: Herman Hollerith

American Inventor

• developed devices that were able to read information which had been punched into cards automatically
• developed a machine called the census machine

US Census Bureau.

Capable of reading numbers, characters, and also special symbols.

Harvard Mark I

• 1944: Howard Aikens and Grace Hooper  developed an electromechanical machine at IBM
• Called Automatic Sequence Controlled Calculator (ASCC)
• Called Mark I by Harvard University
• Capable of reading numbers, characters, and also special symbols
• Built from Switches, Relays, rotating shafts and clutches
• 765,000 components
• Hundred of meters of wires
• Volume
• Length  (51ft)  X Height (8 ft) x Depth  (2 ft)
• Weight   4500 kgs
• Used decimal number systems

ENIAC

• 1946  First general purpose electronic computer
• Electronic Numerical Integrator And Computer (ENIAC)
• Technology used

Vacuum tubes   17,468

Crystal Diodes    7,200

Relays    1,500

Transistors  70,000

Capacitors  10,000

Hand soldered joints  1 million

• Weight  27 tons
• Volume  100 ft (L) X 8 ft ( H) X 3 ft (D)
• Covers 1800 sq. feet
• Power consumption  150 kW
• Uses punch cards
• Averages 5,000 operations

Manchester Mark I

• 1948
• First stored program computer,
• Based on Von Neumann architecture
• Manchester Mark 1 , built in UK. Using valves ,
• it can perform about 500 operations  per second and has the first RAM .
• It fills a room  the size of a small office.

Ferranti Nimrod Computer

1951 : Early computer game , Nim

Played by Ferranti Nimrod computer at the Festival of Britain.

History of Microcomputers

1965 DEC PDP 8 produced in US

First commercially successful microcomputer,

Programmed Data Processor (PDP)

It sits on a desktop

H 316 Kitchen Computer

1965  Honeywell corporation

First home computer

Costs $10,600

Intel 4004 Microprocessor

• 1971 Intel 4004, the world’s first commercially available microprocessor.
• four-bit computer containing 2,300 transistors
• can perform 60,000 instructions per second.
• Designed for use in a calculator
• Sells for $200

Floppy Disks

• 1972 : 5.25-inch floppy diskettes are introduced
• providing a portable way to store and move data from machine to machine.

Intel 8008 Microprocessors

• Intel announces the 8008 chip.

2-MHz, eight-bit microprocessor

can access 64 KB of memory

used a two-byte addressing structure

over 6000 transistors on one chip

can perform640,000 instructions per second.

• Motorola introduces the 6800 microprocessor.

8 bit processor

used primarily in industrial and automotive devices.

Altair 880

1975, first commercially available microcomputer

• 64 KB of memory
• open 100-line bus structure.
• sells for $397 in kit form or $439 assembled.

Apple I

1976 Steve Wozniak and Steve Jobs build the Apple I computer.

• less powerful than the Altair, but also less expensive and less complicated.
• Users must connect their own keyboard and video display, and
• have the option of mounting the computer’s motherboard in any container they choose — whether a metal case, a wooden box, or a briefcase.

Commodore PET

1977 Mass produced personal computer,

Commodore PET (Personal Electronic Transactor ) appears.

Osborne I

• 1981 First portable computer, Osborne 1, produced.
• At the size and weight of a sewing machine,

much less convenient than current portable computers.

weighs about 22 pounds

Two 5.25-inch floppy drives,

64 KB of RAM, and

a five-inch monitor but no hard drive.

based on the z80 processor, runs the CP/M operating system, and

sells for $1,795.

The Osborne 1 comes with WordStar (a word processing application) and Super-Calc (a spreadsheet application).

It is a huge success.

IBM PC

1981, IBM introduces the IBM-PC

• 4.77 MHz Intel 8088 CPU,
• 16 KB of memory,
• a keyboard,
• a monitor,
• one or two 5.25-inch floppy drives, and
• A price tag of $2,495

Apple

1984  Apple Macintosh computer becomes first successful personal computer with a mouse and easy to use Graphic User Interface (GUI).

Windows, Laser Jet

• Intel releases the 80386 processor (also called the 386),

a 32-bit processor that can address more than four billion bytes of memory and performs 10 times faster than the 80286.

• Aldus releases Page-Maker for the Macintosh,

the first desktop publishing software for microcomputers.

• Microsoft announces the Windows 1.0 operating environment,

featuring the first graphical user interface for PCs mirroring the interface found the previous year on the Macintosh.

• Hewlett-Packard introduces the LaserJet laser printer, featuring 300 dpi resolution.

Generation of Computers

Generation	Dates	Characteristic
1st	1944-59	Use Valves (Vacuum tubes)
2nd	1959-64	Use transistors
3rd	1964-75	Large Scale Integrated Circuits
4th	1975-	Very Large Scale Integrated Circuits
5th	Under development	“Artificial Intelligence” based computers

Summary

Course Outline

What is a computer?

Comparison of Computer with Human

History of Computers

Developments in Microcomputers