Types of Computer

Lecture: 2

Types of Computer (On the Basis of Functionality)

According to functionality computer can be divided in to three types:

Analog Digital Hybrid

Analog Computer

An analog computer is a form of computer that uses the continuously-changeable aspects of physical fact such as electrical, mechanical, or hydraulic(moved or operated or effected by liquid) quantities to model the problem being solved.”

Analog means continuity of associated quantity just like an analog clock measures time by means of the distance traveled by the hand of the clock around a dial.

Analog Computer Analog computer measures and answer the questions by

the method of “HOW MUCH”. The input data is not a number infect a physical quantity like temperature, pressure, speed, velocity

Used in World War II and the Korean War. They were commonly used in science and industry

before the Digital Computer EXAMPLES: Thermometer Analog clock Speedometer Tire pressure gauge

Digital Computer “A computer that performs calculations and

logical operations with quantities represented as digits, usually in the binary number system of “0” and “1”.

“Computer capable of solving problems by processing information expressed in discrete form.

Digital computer counts and answer the questions by the method of “HOW Many”. The input data is represented by a number. These are used for the logical and arithmetic operations.

Digital Computer

By manipulating combinations of binary digits (“0”, “1”)

o Mathematical calculationso Organize and analyze datao Control industrial and other processes.

Digital Computer

EXAMPLES: IBM PC Apple Macintosh Calculators Digital watches etc

Hybrid Computer:“A computer that processes both analog and

digital data”.“Hybrid computer is a digital computer that

accepts analog signals, converts them to digital and processes them in digital form”

Hybrid Machines are generally used in scientific applications or in controlling industrial processes.

Hybrid Computer: Examples: Hybrid computer is the computer used in

hospitals to measure the heartbeat of the patient.

Radar is also an example of hybrid computer

Classification of Computer

(On the Basis of size capacity and speed)

Super Computers Leads the world in terms of processing capacity, particularly

speed of calculation Can handle gigantic amount of scientific computation About 50,000 times faster than micro-computers Used primarily for engineering and scientific problem

analysis as well as for computerized graphics and special effects seen in films.

Cost as much as $20 million

A super computer contains a number of CPU which operate in parallel to make it faster. It also known as grand father computer.

In areas like: Defense(Missile

Technology) Weather forecasting Scientific research Drug discoveries Hollywood movies

Examples of Super Computers are CRAY X1 and CRAY T90

Mainframe Computers

Smaller and less powerful than supercomputer

Can support hundreds and thousands of users

used mainly by large organizations for critical applications, typically bulk data processing(i.e. huge storage capacity and massive processing ability)

These are large and fast computers usually housed in a controlled environment.

Multi-user environment, have the ability to service more than 100 terminals at a time

TERMINALS – are the points from which users can have access to the services of a multi-user computer.

Terminals (which look like a microcomputer) are used to enter and retrieve data from mainframe computers.

They can support the processing requirements of hundreds and even thousands of users.

Are the largest, fastest and most expensive computers in commercial use today.

Of all types of computers, mainframe have been around the longest. ENIAC(Electronic Numerical Integrator And Calculator) and UNIVAC(Universal Automatic Computer) were mainframe computers.

Is the smallest computer designed specifically for the multi-user environment.

This type of computer can allow several persons to use the machine at the same time.

Can process up to millions of characters. Before the late 60’s, most computers

produced were mainframe computers and they were very expensive.

The prohibited price of mainframes limited its buyers to only the largest companies.

Mini Computers

A smaller and more affordable version of mainframe and thus what the minicomputer was born.

Their storage capacities are smaller and they service fewer terminals as compared to mainframes.

A computer servicing more than 100 terminals is no longer called a minicomputer.

The major difference between the mainframe and minicomputer is in the number of terminals they can service.

Micro Computer A personal computer; designed to

meet the computer needs of an individual.

Provides access to a wide variety of computing applications, such as word processing, photo editing, e-mail, and internet.

The major difference between microcomputers and the larger minicomputers and mainframes is that micros are generally single-user but a multi-tasking machine.

Micro Computers

Personal Computers (PC) occupy physically small amounts of space

Low Power Consumption Example:

Desktop computers laptop computers handhelds

Desktop Microcomputer

Bigger in Size No Portability Input & Output devices

are connected separately to System Unit

Has separate components (keyboard, mouse, etc.) that are each plugged into the computer.

Laptop Computer

A portable, compact computer that can run on an electrical wall outlet or a battery unit.

All components (keyboard, mouse, etc.) are in one compact unit.

Usually more expensive than a comparable desktop.

Sometimes called a Notebook.

Handheld Also called a PDA (Personal

Digital Assistant). A computer that fits into a pocket,

runs on batteries, and is used while holding the unit in your hand.

Typically used as an appointment book, address book, calculator, and notepad.

Smaller in Size and Fully Portable Speed is less than Desktops &

Laptops Capable of running specific

Application Software (System Software are limited)

Can operate for days on its batteries

A tablet PC is a wireless personal computer (PC) that allows a user to take notes using natural handwriting with a stylus or digital pen on a touch screen.

The user's handwritten notes, which can be edited and revised, can also be indexed and searched or shared via e-mail or cell phone.

Touch Panel with Electronic Pen

Tablet PC

Slide 24

Workstations are similar like Desktop PCs but unlike desktops, they have high end processing speed for specific software

Used for Graphic Designing, Special effects for movies, CAD applications

Special Input and Output devices are provided to Power Users

Workstations

Embedded Computers

An embedded computer is a special-purpose computer that functions as a component in a larger product

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Servers A server is a large shared computer

several times the power of a workstation several times the memory of a workstation hardware and operating system optimisedfor multi-user, no-crash operation

A server may act as one or more of: compute server: to run programs file server: to store files centrally mail server: to route mail messages web server: to store web files etc

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