Introduction to Computers

& Classification of

Computers

Lecture# 1

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This lesson includes the following sections:• Parts of Information Processing Cycle

• Components of Computer System

• Software: Bringing the Machine to Life

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A World of ComputersWhat is computer literacy or Digital Litracy?

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Knowledge and understanding of computers and their uses

Computers are everywhereMaybe a better term : Computer Fluency (adaptability)

What Is A Computer?A computer is a Processing Device. Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations.

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Collects data (input) Processing Produces information (output)

• People are the computer's operators, or users.

• Power User—A sophisticated user of personal computers.

• A power user is typically someone who has considerable experience with computers and utilizes the most advanced features of applications.

• Some types of computers can operate without much intervention from people, but personal computers are designed specifically for use by people.

Users

Information Processing CycleWhat is the information processing cycle?A machine that performs the four basic operationsof the information-processing cycle:

Input Process Output Storage

Collects data (input) Processing

Produces information

(output)

Information Processing Cycle

Input: Getting Data into the Computer

• Data – Unorganized raw materials made up of words, numbers, images, or sounds

• The first operation: input– First operation of the information-

processing cycle, enables the computer to accept data

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Processing: Transforming Data into Information

Processing Second operation of the information-

processing cycle, converts data into information

Information refers to consolidate, organized, processed data.

The central processing unit (CPU) processes data into information.

Random access memory (RAM) temporarily stores programs and data needed by the CPU.

DATA IN INFORMATION OUT

Processor

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Output: Displaying Information

• The third operation: output– The computer shows the results of the processing

operation in a way people can understand

Storage: Holding Programs and Datafor Future Use

• The fourth operation: storage– The computer saves the data or output so that it

can be used again later

• Data consists of raw facts, which the computer can manipulate and process into information that is useful to people.

• Computerized data is digital, meaning that it has been reduced to digits, or numbers. The computer stores and reads all data as numbers.

• Although computers use data in digital form, they convert data into forms that people can understand, such as text, numerals, sounds, and images.

How Computers Represent Data

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How Computers Represent Data • All symbols, pictures or words must be reduced to a

string of binary digits.• A binary digit is called a bit and represents either a 0

or a 1. • These are the only digits in the binary or base 2,

number system used by computers.• A string of eight bits used to store one number or

character in a computer system is called a byte

COMMON CODING SYSTEMS

• When numbers, letters or words are represented by special group of symbols is called Code.

• Two common coding systems are Extended Binary Coded Decimal Interchange Code (EBCDIC) and American Standard Code for Information Interchange (ASCII).

• EBCDIC represents every number, alphabetic character, or special character with eight bits, used primarily in IBM and other mainframe computers.

American Standard Code for Information Interchange

American Standard Code for Information Interchange (ASCII), is a universally accepted alphanumeric code used in most computer and other electronic equipments.

Most computer keyboards are standardize with ASCII. When you enter a letter, number or control command, the equivalent ASCII

codes goes into the computer. ASCII has 256 characters and symbols represented by 8-bit code series. The first 32 characters represents the control characters that are not printed or

displayed. The other characters are graphic symbols that can be printed or displayed. e.g. alphabets, ten decimal digits, punctuation signs, other sysmbols.

• A computer uses two types of Memories. A main memory consisting of ROM and RAM, and backing stores which can be internal, e.g. hard disk, or external, eg a CD or USB flash drive.

RAM• Memory also consists of chips attached to the motherboard.• Memory holds data and program instructions as the CPU works with them.

This memory is called Random Access Memory (RAM).• The CPU can find any piece of data in RAM, when it needs it for processing.• RAM is volatile, meaning it holds data only when the power is on. When

the power is off, RAM's contents are lost. ROM ( Read Only Memory)• ROM is an acronym for Read-Only Memory. • It refers to computer memory chips containing permanent or semi-

permanent data. Unlike RAM, ROM is Non-volatile. • The contents of ROM remain even after the computer is switched off. A

computer comes with a small amount of ROM containing the boot firmware. On a PC, the boot firmware is called the BIOS.

•  ROM stores the instructions for the computer to start up when it is turned on again.

• This consists of a few kilobytes of code that tell the computer what to do when it starts up, e.g., running hardware diagnostics and loading the operating system into RAM.

Memory

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• The smallest usable unit of measure for memory is the byte – the amount of memory required to hold one character, like the letter A or the numeral 2.

• Computers work with larger chunks of data, measured in multiple bytes, as shown below:

How Memory is Measured

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Size Equal to

8 bits 1 Byte1024 bytes 1 KiloByte1024 kilobytes 1 MegaByte1024 megabytes 1 GigaByte1024 gigabytes 1 TeraByte

Relationship between measurement

File File size

Photo 3MB

Song 5MB

Film 700MB-4.5 GB

Example file sizes:The table below lists files commonly found on a computer and their typical file size (compressed):

A file’s size can be influenced by a number of factors but ultimately the more information a file stores, the larger it will be.

Computer Fundamentals

• Computer system—group of associated components that work together– Hardware– Software

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The Components of a Computer

• A computer contains many electric, electronic, and mechanical components known as hardware

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• Allows you to enter data and instructions into a computerInput Device• Hardware component that conveys information to one or

more peopleOutput Device• Case that contains the electronic components of the computer

that are used to process dataSystem Unit• Records (writes) and/or retrieves (reads) items to and from

storage mediaStorage Device• Enables a computer to send and receive data, instructions,

and information to and from one or more computers or mobile devices

Communications Device

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The Components of a Computer

Discovering Computers 2012: Chapter 1 22

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List of input & Output Devices Input Devices:a) Graphics Tabletsb) Camerasc) Video Capture Hardwared) Trackballse) Barcode readerf) Digital camerag) Gamepadh) Joysticki) Keyboardj) Microphonek) Mouse (pointing device)m) Scannern) Webcamo) Touchpadsp) Pen Inputq) Microphoner) Electronic Whiteboard

Output Devices:1. Monitor2. Printers (all types)3. Plotters4. Projector5. LCD Projection Panels6. Computer Output Microfilm (COM)7. Speaker(s)

Both Input-OutPut Devices:8. Modems9. Network cards10. Touch Screen11. Headsets (Headset consists of Speakers and

Microphone. 12. Speaker act Output Device and

Microphone act as Input device)13. Facsimile (FAX) (It has scanner to scan the

document and also have printer to Print the document)

14. Audio Cards / Sound Card

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Computer SoftwareWhat is software? 1. A software is a set of instructions that make a the hardware to operate and

govern the operation of computer and enable a user to interact with the computer or have the computer perform specific tasks for them. Without software, the computer would be useless.

2. Instructions and code written by programmers in any of various special computer languages.

3. For example, without your Internet browser software you would be unable to browse the Internet or read this page and without a software operating system the browser would not be able to run on your computer.

4. Software is "virtual," or intangible / not physical like computer hardware. 1. Types of Software: Software can be classified into following two main

categories or types: 1-Operating System 2- Application Software

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Computer SoftwareWhat is Operating System?

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Programs that control or maintain the operations of the computer and its devices.

Operating System consists of the programs that carryout computer basic operating tasks: loading program, executing program, saving data to disks, displaying information to output devices, and transmit data through ports to a peripheral devices, Administrative security

The Operating System have instruction that coordinate the activities of the hardware devices.

Firmware is software built into chips (hardware) like that in cell phones and PDAs

Windows Linux MacOS

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Computer SoftwareWhat is a graphical user interface (GUI)?

Allows you to interact with the software using graphics and visual images such as icons.

Controls how you enter data and instructions and how the screen displays information

Pointer : A symbol that appears on the display screen and that you move to select objects and commands. Usually, the pointer appears as a small angled arrow. Text -processing applications, however, use an I-beam pointer that is shaped like a capital I.

Pointing device : A device, such as a mouse or trackball, that enables you to select objects on the display screen.

Icons : Small pictures that represent commands, files, or windows. By moving the pointer to the icon and pressing a mouse button, you can execute a command or convert the icon into a window. You can also move the icons around the display screen as if they were real objects on your desk.

Desktop : The area on the display screen where icons are grouped is often referred to as the desktop because the icons are intended to represent real objects on a real desktop.

Windows: You can divide the screen into different areas. In each window, you can run a different program or display a different file. You can move windows around the display screen, and change their shape and size at will.

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Computer SoftwareWhat is application software?

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• Applications software is computer software designed to help the user to perform singular or multiple related specific tasks.

• They act as instructions which direct the hardware to perform specific functions and examples of such include accounting software, office suites, graphics software and media players.

• Application software is the software you use to get things done. • Programs designed to make users more productive Help the user to work more effectively and efficiently. • These programs can be stand alone software packages or they can often

be purchased or downloaded as a bundle. • Most productivity software includes a word processing application (such

as Word), a spreadsheet application (such as Excel), and presentation software (such as Power Point.)

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Classification Of Computers

Type of computer

Digital computer

Micro Computer

Workstation

PC

Mini Computer

MainframeComputer

SuperComputer

Analog computer

Hybrid Computer

Classification of Computers:

Analog Computers:• Analog computers are used to process analog data. • Analog data is of continuous nature and which is not discrete or

separate. Such type of data includes temperature, pressure, speed weight, voltage, depth etc.

• These quantities are continuous and having an infinite variety of values.• Output from an analog computer is generally in the form of readings on

a series of dial (Speedometer of a car) or a graph on strip chart.

Digital Computers:

• Digital computers are those computers that specialized in counting.• The digital computer handles values that that are in a discrete (0 or 1). • All commonly used computers are digital

.

Hybrid Computers:• A hybrid is a combination of digital and analog computers.• It combines the best features of both types of computers, i-e. It has the speed of

analog computer and the memory and accuracy of digital computer. • Hybrid computers are used mainly in specialized applications where both kinds

of data need to be processed. Therefore, they help the user, to process both continuous and discrete data.

• For example a petrol pump contains a processor that converts fuel flow measurements into quantity and price values. In hospital Intensive Care Unit (ICU), an analog device is used which measures patient's blood pressure and temperature etc, which are then converted and displayed in the form of digits. Hybrid computers for example are used for scientific calculations, in defense and radar systems.

Classification of Computers

• Computers can be separated into two main types:– Individual—designed for one user at a

time– Organization—designed to be used by

many people at the same time

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ServersWhat types of servers are there?

Mainframe Very powerful, expensive computer that supports thousands of connected users[Also called an Enterprise Server]Supercomputer The fastest, most powerful, most expensive computer. Used for applications requiring complex mathematical calculations

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Server Controls access to network resources and provides centralized storage

The Tianhe-2 super computer , the world’s fastest computer. Its speed is 33.9 petaflops meaning that it can perform quadrillions of calculations every second

A supercomputer may be a built as a single machine or may consist of a cluster of computers that process data in tandem.

Minicomputers

• Minicomputers are smaller than mainframes but larger than microcomputers. • Minicomputers are also used as network servers and

Internet servers like mainframes computer and super

computer in small organization. HP

MediaSmart Server

Personal ComputersWhat is a desktop computer?

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Designed so all of the components fit on or under a desk or table

A personal computer is a computer that can perform all of its input, processing, output, and storage activities by itself.

These micro-computers contain a processor, memory, and one or more input, output, and storage devices. Personal computers also often contain a communications device.

The main reason behind the importance of the PCs is that they are not very expensive for the individuals or the small businesses.

Some of the major PC manufacturers are APPLE, IBM, Dell and Hewlett-Packard 

Apple computers, such as the iMac, usually use a Macintosh operating system.

Mobile Computers and Mobile DevicesWhat is a notebook computer?

Portable, small enough to fit on your lap Generally more expensive than desktop computers with

equal capabilities A laptop is a portable computer that a user can carry

around. Since the laptop resembles a notebook, it is also known

as the notebook computer. Laptops are small computers enclosing all the basic features of a normal desktop computer.

The biggest advantage of laptops is that they are lightweight and one can use them anywhere and at anytime, especially when one is travelling.

Moreover, they do not need any external power supply as a rechargeable battery is completely self-contained in them.

Mobile Devices/ Hand-held Computers: Mobile devices, which are small enough to carry in a pocket/bag. Store programs and data permanently on memory inside the

system unit or on small storage media such as memory cards. You connect a mobile device to a personal computer to exchange information. Some mobile devices are Internet-enabled and Connect to the

Internet wirelessly. Because of reduced size, the screens on handheld computers

are small. Popular types of mobile devices are smart phones and PDAs, e-book readers, handheld computers, portable

media players, and digital cameras.

The iPad is a widelyused slate tablet.

Embedded ComputersWhat is an embedded computer?

A special-purpose computer that functions as a component in a larger product.

Computer system that is part of a larger system and performs only peripheral functions (such as guidance or security) but no data processing function.

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