Week 1Lecture #1, 2

Introduction to computer

SystemA set of detailed methods, procedures, and

routines established or formulated to carry out a specific activity, perform a duty, or solve a problem.

Sub-systemA major part of a system which itself has

the characteristics of a system, usually consisting of several components.

Computer SystemA complete, working computer along with

softwares and peripheral devices that are necessary to make the computer function is called Computer system. Every computer system requires an operating system to operate.

Computer System

Lets enter in the world of computers…..!!!!

Computer Literacy (Digital Literacy)

Why we use Computers ?

Why we need It ?

Computers are present in every aspect of daily living –in the workplace, at home, in the classroom, and for

entertainment

An electronic machine that can accept data (input), manipulate the data according to specified rules (process), produce results (output), and stores the results for future use.

What is a Computer?

What is a Computer?An electronic device designed to accept

data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations.

Data VS Information

Data Collection of raw facts and figures.Information processed form of data which is

meaningful.

Information processing cycleSeries of input, processes, output and

storage.

A computer often holds data, instructions and information for future use.

The Components of a Computer

Input devicesOutput devices System unitStorage devicesCommunications devices

The Components of a Computer

AdvantagesIt helps you automate various tasks that you

can/cannot do manually.It helps you organize and store your bulky

data and information in a better way. It has much more computing and calculating

power than an ordinary human. It may help your work to be a lot easier. It may be the storage of your important data

and files.

AdvantagesIt may be your handy book. It may help you solve problems faster than

an ordinary human being can do. It has speed, storage, reliability,

consistency and communications.It helps you to find useful information using

the Internet. It helps in businesses, factories, offices,

schools and homes.

Disadvantage It destroys your social life and interactions

with humans if you do not maintain the balance.

It may effect to the destruction of your eye sight due to radiation.

It may damage your studies and life.

Disadvantage The way it distracts and can deviate our

thoughts and activities towards un-productive activities.

It could cause violation of privacy, impact on labor force, health risks, impact on environment, distraction from work, and antisocial influences.

Types of Computer Computer types can be divided into 3 categories

according to electronic nature.Analog Computer Digital Computer Hybrid Computer

Analogue ComputerAnalogue types of Computer uses analogue

signals that are represented by a continuous set of varying voltages and are used in scientific research centers.

Analogue Signal and Analogue Devices

Digital Computer A computer that stores data in terms of digits

(numbers) and proceeds in discrete steps from one state to the next. The states of a digital computer typically involves binary digits which may take the form of the presence or absence of magnetic markers in a storage medium. In digital computers, even letters, words and whole texts are represented digitally.

0,1False trueLow high

Digital Signal and Digital Devices

Hybrid ComputersDesigned to display the features and

characteristics of both analog and the digital computers.

When the hybrid computers are used in the form of digital computers then they are deigned to act as the controller for the operations carried out in the system.

When analog is taken into account then in that case the computer acts as a solution provider for different problems that exit.

By depicting both the feature, it is found to be a beneficial computer.

Examples of Hybrid Computer

Classification of Computer

There are two types of classesClasses by size Classes by Functions

Classes by size

Microcomputers (Personal computers)Minicomputers (Midrange computers)Mainframe computersSupercomputer

Classes by functions ServersWorkstationsInformation appliancesEmbedded computers

Microcomputers Microcomputers are the most common type of

computers used by people today, whether in a workplace, at school or on the desk at home. e.g.

Desktop computers Game consoles LaptopsNotebook computersPalmtop computersTablet PC Programmable calculator

Palmtop Computers

Tablet PC

Notebook Computers

Programmable calculators

Game Console Laptops

MinicomputersContemporary term for this class of system

is midrange computer.Lies in the middle range of the computing

variety in between the smallest multi-user systems (mainframe computers) and the largest single-user systems (microcomputers or personal computers), Power between mainframe and desktops.

Class of multi-user computers handled by hundred of users.

MinicomputersUsed in smaller organizations.Initially these had category between

mainframe and personal computers.Now a days we use server machine instead

of mini computers.such as the higher-end SPARC, POWER and

Itanium -based systems from Sun Microsystems, IBM and Hewlett-Packard.

Mini computers

Mainframe computersUsed in large organizations.A very large and expensive computer

capable of supporting hundreds, or even thousands, of users simultaneously.

Also called enterprise servers.There are multiple processors in these

computers(2,4,12).Banks and shopping marts are

interconnected through mainframe computers.

Main frame computers

Super Computers All of the resources to tackle one problem Used for very complex operations 1. Rocket launching 2. Assembling 3. Weather prediction 4. Aeronautics 5. Testing of nuclear weapons Cray one 160 millions instructions /second 160 trillion bytes storage 6 trillion bytes memory

Super Computers

Comparison between Minicomputer, Mainframe & SupercomputerIn some ways, mainframes are more

powerful than supercomputers as they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe.

The distinction between small mainframes and minicomputers is vague, depending really on how the manufacturer wants to market its machines.

Hierarchy of Computers In the hierarchy starting with a simple

microprocessor (watches) at the bottom supercomputers at

the top, mainframes are just below super

computers.

Comparison TableCategory of computer

Number of simultaneous users

Size of computer

Personal computer(desktop)

Fits on a desk Usually one(more if networkerd)

Mobile computer and Mobile devices

Fits on your lap or in hand

Usually one

Game console Small box or hand held device

One to several

Server Small cabinet Two to thousands

Mainframe Partial room to full room of equipment

Hundred to thousands

Super computer Full room of equipment

Hundred to thousands

Embedded computer

Miniature Usuaally one

Servers

Server is a physical computer (a hardware system) dedicated to running one or more such services (as a host) to serve the needs of users of the other computers on the network.

Types of ServerDepending on the computing service that it

offers it could be1.Database server2.File server3.Mail server4.Print server 5.Web server

Database ServerProvides database services to other computers

as defined by the client-server model.DBMS provide database server functionality, In a master-slave model, database master

servers are central and primary locations of data while database slave servers are synchronized backups of the master acting as proxies.

e.g.Oracle, DB2, SQL server

File Server Computer attached to a network with

primary purpose of providing a location for shared disk access,

i.e. shared storage of computer files (such as documents, sound files, photographs, movies, images, databases, etc.) that can be accessed by the workstations that are attached to the computer network

Mail ServerEvery email that is sent passes through a

series of mail serversA complex series of transfers takes place. Without this series of mail servers, email

can be sent to the email address of the same domain.

Server

Client Server Network

Workstations

In networking, workstation refers to any computer connected to a local-area network. It could be a workstation or a personal computer.

Information applianceIn information appliance or information

device is any machine or device that is usable for the purposes of computing, telecommunicating, reproducing, and presenting encoded information in innumerable forms and applications.

Information appliances

Embedded Computers Embedded computers can be compared to

"computers on a chip". All in one , so to speak. You will find them in all kind of devices surrounding us where you need to regulate something, control or check something

e.g. Home automation devices e.g. Washing

machines, Sewing machines, Microwave Ticket machines at the subway, Cameras, clocks Cell phone, Video games, Global

Positioning System Automobiles, cars, motors (antilock brakes)

Mobile DevicesHandheld ComputersPDASmart PhonesGPS

Hand Held Computers

Personal Digital Assistant (PDA)

Smart phones

Global Positioning System