Parallel Processing Computers

• Mainframe power computer that uses more than one processor (e.g. 8 - 256 processors)

• Used to serve several transactions simultaneously (e.g. ATM)

Evolution of Microprocessors

• Intel

• 8086, 80286, 80386, 80486, Pentium

• Motorola

• 68000

• Cyrix

• AMD

First microprocesser is Intel 4004

INPUT DEVICES

Accept data & instructions from the user or from another computer system & converts them to the machine readable form.

The form of the input may be by means of

1. Keyboard & Pointing devices (mouse, track ball, joy stick, touch screen)

n A mouse is a device that can be rolled on a desktop to direct a pointer (cursor) on the

computers display screen. The cursor is the

symbol on the screen that shows where data

may be entered next or the command to be

activated.

n Pointing devices commonly have two or three

buttons that are used to issue commands to the

computer.

n A trackball performs like a stationary, upside-down mouse.

A joystick is a small lever that can be moved in any direction to move an object on the screen.Usually associated with playing computer games.

Classification of Computers

Classification of Computers

• Super Computers
• Mainframe Computers.
• Minicomputers.
• Microcomputers.
• Special Purpose Computers.
• Lap tops
• Palm tops
• Work Stations
• Servers


Comparison of Computers
Computers have become
• Faster (more powerful and more memory),
• Cheaper (cost less) and
• Smaller in size
Supercomputers
• Sophisticated, expensive computers, Provide processing speeds, many times that of powerful workstations.
• Particularly used in the simulation and modeling of complex systems.
e.g. weather, chemical processes, the US economy, motion of galaxy

Mainframe Computers
• A multi-user computer designed to meet the computing needs of a large organization.
• Originally the term referred to the metal cabinet housing the CPU.
• Generally refers to computers of the 1950s and 1960s.
• Can process a number of applications concurrently.
• Used by large organisations to handle millions of transactions.
• Usually housed in specially wired air-conditioned rooms.


Minicomputers
• Scaled down mainframe. (refrigerator-size)
• Designed to meet the computing needs of a department or small company. Typically 4-100 users.
Can support a number of concurrent applications.

Microcomputers
• Appeared mid-to-late 70s.
E.g. Apple II, Sinclair Spectrum, Commodore PET
• Portable models now available
• Small computers that can fit on a desktop or briefcase.
• There are two types
• Personal Computers (PC)
• Workstations

Personal Computer (PC)
• Desktop or portable (laptop, notebook, palmtop).
• Used in most organisations and at homes.
• Commonly used for easy-to-use programs such as word processing, spreadsheets.
Workstations
• Connected to large computer system.
• Designed to work with large or complex applications.
.e.g. drafting, engineering design, 3D-graphical models

Fundamentals of IT

What is a Computer?

Computer is a man made programmable electronic machine which can store, retrieve and process data into information according to the instructions given.

Data + Instructions – Information

What is Data?

Raw facts that are to be processed

What is Information?

Processed Data with meaning

Characteristics of the Computer

Comparative to human

Advantages

1 Speed

2 Accuracy GIGO Garbage in garbage out

3 Diligence free from tiredness

4 Versatility could perform different tasks

5 Power of remembering

Disadvantages

No IQ

No feelings

History of Computer.

Mechanical Age

• Abacus – First man made computing device is ABACUS It is a calculating device (3000 BC) Small beads are arranged on vertical rods

This is still used in China. Russia & Far East

• Pascaline - Mechanical adding machine (1642) Pascal used wheels to move beads

• Von Leibnitz made improvements in the Pascals machine in 1674. Addition, Subtraction, Multiplication, Division could be done

• Joseph Jacquard introduced the punch card system for the weaving industry(1800)

• Charles Babbage (Father of Computers) English mathematician in 19th century Using the punch card system he invented the analytical engine. This was not successful as the mathematics knowledge at that time was not adequate. This machine could store 1000, 50 digit numbers for calculations & decisions.He called this the analytical engine (1830s)

He also invented the Difference Engine

.Ada Love lace-World's first programmer (1800s)

Hollerith - tabulating machine (1890s)He introduced a system to process census data in United States in 1890 using punched card system

• The code developed by Hollerinth is called the Hollerinth code

ELECTRONIC AGE

1900 - 1945

Howard Aiken using Babbages concept invented MARK I a calculator in 1944. MARK I used a typewriter as the input & punched cards as the

output. Weighed 15 tons.

1 st generation (1946)

ENIAC (Electronic Numerical Integrator & Computer) was the first electronic digital computer built in 1946. ENIAC used the vacuum Tube technology.

In 1950 Remington Rand manufactured the

UNIVAC 1 (Universal Automatic Calculator) first machine to use magnetic medium for input and output.

In 1957 IBM (International Business Machine) Corporation developed IBM 704 which could perform 100000 calculations per second.

2 nd generation (1950)

Late 1950 transistors were invented and replaced vacuum tubes. It could perform 200,000 – 250,000 calculations per second.

Tapes were used for output.

3 rd generation ( 1959 1965 )

Integrated circuits replaced the transistors. Magnetic discs were used for storing.

4 th generation (1971)

Integratcd circuits were coupled and formed LSI (Large Scale Integration) and VLSI ( Very Large Scale Integration) which formed microchips. Multi-programming and virtual storage memory were introduced.

5^th generation (1980)

These computers operated at a speed of 3 to 5 million calculations per second.