chapter 1 computer concepts

7/31/2019 Chapter 1 Computer Concepts

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Chapter 1 : Computer Concepts


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Objectives

At the end of this module you should be able to: Explain how computer works

State the functions of each basic hardwarecomponent of a computer system

Classify computers


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Computer

is an electronic device that accepts data, storesand processes the data and generatesinformation as output.


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Computer (storesand process data)Data

inputinfo

output

A computer


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Data and Information

Data is a raw, unprocessed data

Information is a processed data


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Four Basic Functions:

Input the procedure of feeding data into acomputer

Process refers to the operation ofmanipulating and transforming data intosomething useful.

Program a set of written instructions, is what tells thecomputer how to manipulate and transform the data itwas given into information

Output the result of the processing function. Storage computers can save data so that ir can

be used at another time.


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SAQ 1-1

How does the computer process data?


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ASAQ 1-1

The computer processes data by following a setof instructions called a program


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Computer Systems Components

Hardware refers to the tangible components ofa computer system

Software refers to the set of instructionswritten in a code.


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Basic Hardware Components

Input devices perform the two most basiccomputing tasks : issuing commands andentering data.

Data entry defined as the process of entering datainto the computer memory and issuing commandsthat tell the processor how to work with the data.


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Examples of Input device:

Keyboard

Mouse

Trackball

Joystick

Lightpen

Video input device Scanners


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Output Device

after processing data fed into the computer withthe use of input devices, the information mustnow be outputted in a form understood by humanbeings. For this purpose, computer systemcomponents collectively called as output devices

are used.


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Examples of Output device:

Printer

Video monitors

Speakers

modem


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Central Processing Unit (CPU)

CPU does the data processing. Its job is to fetch

instructions (programs) from the main memory,decode, and execute it.


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Parts of a CPU:

Control Unit (CU)

Performs the arithmetic and logical operations

using some electronic circuitry.

Arithmetic Logic Unit (ALU)

Involves comparing two items and determining

whether one is greater than, equal or less than theother.


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SAQ 1-2

What specific components of the computer doesthe arithmetic computations?


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ASAQ 1-2

The arithmetic/logic unit (ALU)


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Main Memory and Secondary Memory

when the CPU processes the data, it uses the

memory as temporary storage to aid in thecalculations.


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Bits and bytes

The data and programs are stored in thememory in the form of binary digits (0 and 1).

Numbers are all represented using the binarysystem, and text and characters are coded inbinary.

8 bits = 1 byte 1024 bytes = 1 kilobyte

1024 kilobytes = 1 megabytes

1024 megabytes = 1 gigabyte


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Computer Memory

Consists of the main memory and the secondarymemory. The difference between the two types

of memory lies in the technology used.

Main Memory stores data using electric

current flowing around the loop of wire.

Secondary Memory usually uses magneticmaterials, just like those found in cassette tapes.


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Comparison of Computer MemoryMemory

TypeTechnology Limitations, Advantages and

Disadvantages

Main Memory Uses electric current -Very expensive-Fast access-Volatile

SecondaryMemory

Uses magneticmaterials

-Relatively cheap-Slow access-Non-volatile


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SAQ 1-3

Why do computers need to use both types ofmemories (main and secondary)?


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ASAQ 1-3

It uses main memory to be able to process dataat high speeds (remember how the memory is

used as temporary storage?) and it usessecondary memory to preserve data.


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COMPUTER SOFTWARE

It can be categorized into two classes :

Applications Software

System Software


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Application Software

Are programs that are used by people to solvetheir individual needs.

Examples:

Word Processor

Spreadsheet programs


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Systems Software

Are programs that control the operations of thecomputer hardware.

Task of Systems Software

Starting up of the computer

Loading

Executing applications software.


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CLASSIFICATION OF COMPUTERS

Computers are usually classified according totheir sizes and processing speeds. But since

technology changes very rapidly, no absolutemeasures to classify computers exist.


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Classification of Computers

Microcomputers

refer to small desktop systems made popular by

IBM in the early 80s. They are also calledpersonal computers and are usually used forindividual tasks such as word processing,spreadsheet computations and other interactive

applications.


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Minicomputers

are more powerful than microcomputer and are

intended to support several users who areconcurrently doing different tasks. They arewidely used in real time applications such as airtraffic control.


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Mainframes

are large systems that can process huge amounts

of data at a very high rate. The main differencebetween mainframes and minicomputers is theirinput/output capacity and the applications forwhich it is used.


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Supercomputers

are the fastest computers and achieve processing

speeds more than 10 times that of theminicomputers. To achieve high speeds, theyusually consists of several processors runningsimultaneously.


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SAQ 1-4

Differentiate microcomputer andminicomputers.


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ASAQ 1-4

Microcomputers are less powerful thanminicomputers. They are designed for

individual use, while minicomputers aredesigned to handle several users at a time.


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HISTORY OF COMPUTERS

Name ofComputer

YearConstructed

Features

Mark I 1994, at HarvardUniversity

-First electromechanical computer- Used electromechanical switching devices

ENIAC (ElectronicNumerical

Integrator andComputer)

1946, atUniversity of

Pennsylvania

-First fully electronic digital computer-Used vacuum tubes

-Worked about 1,000 times as fast as Mark I-Performed approximately 5,000 arithmeticoperations per second

EDVAC (ElectronicDiscrete VariableAutomatic

Computer)

1949 -First computer with program stored in itsmemory-Used vacuum tubes

UNIVAC(UNIVersalAutomaticComputer

1951 -First computer to be mass-produced andcommercially available-Used Vacuum tubes


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SAQ 1-5 What distinguishes the first-generation, second

generation and third-generation computers from

one another?


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ASAQ 1-5 The technology used. First-generation

computers use vacuum tubes, second-generation

computers use transistors and third-generationcomputers use integrated circuits.


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THANK YOU.

chapter 1 computer concepts

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