CDT 04103

1

BASIC STRUCTURE AND FUNCTIONS OF COMPUTERS

VLSI-very large scale integrated technology

CDT 04103

3

Computer is created to simplify jobs of different type according to the user needs.

User of the computer is the one who commands the computer and tells it what to do

User tells computer what to do by entering data using keyboard then result will be displayed on the screen

CDT 04103

4

The process of entering data into computer is called data entry.

This process of entering data to a computer is done by user, in which data will be processed in order to get information

User will use input devices such as keyboard and mouse to enter data in the system then the data will be processed to produce information

The result which is output will be shown in a monitor or through printed document

CDT 04103

5

Below are the procedures and diagram used by computer to execute data

First

Data is entered through input devices e.g. keyboard, Mouse

Second

Control Unit (CU) after receiving instruction from the main memory to send signal and commands, CU send signal and commands to various parts of the computer system to prepare and accept the data

CDT 04103

6

After the data is processed it is sent back to main memory which stores it temporarily before the next command is executed

The data is then sent to secondary storage devices after secondary storage device had received command from the Control Unit

For the information to be put into a hard copy i.e. paper, the information moves from the secondary storage device to the main memory which waits for signals and commands from Control Unit

After receiving signal from the Control Unit that the output devices are ready to receive data, the main memory releases the data to the output devices like printers

CDT 04103

7

Third

Output devices translate the processed information from the computer into a form that humans can understand

The most common output devices are monitors or video display screen and printers.

Lastly

Secondary storage devices hold data and program even after electrical power to the computer has been turned off

The most important kinds of secondary media are floppy, hard and optical disks

CDT 04103

8

Structure of Computer

CDT 04103

9

Computer generation is categorized into five generation

First Generation

Second Generation

Third Generation

Fourth Generation

Fifth Generation

CDT 04103

10

First Generation 1946-1959 (Vacuum year tube).

The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit)

These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organizations

CDT 04103

11

In this generation mainly batch processing operating system were used

Punched cards, paper tape, and magnetic tape were used as input and output devices

The computers in this generation used machine code as programming language

CDT 04103

12

Figure 4: 1st Generation Computer

CDT 04103

13

The Main Features of First Generation

Vacuum tube technology

Unreliable

Supported machine language only

Very costly

Generated lot of heat

Slow input and output devices

Huge size

Need of A.C.

Non-portable

Consumed lot of electricity

CDT 04103

14

Second Generation 1959-1965 (Year of Transistor).

In this generation transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes

In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices

In this generation assembly language and high-level programming languages like FORTRAN, COBOL was used

The computers used batch processing and multiprogramming operating system.

CDT 04103

15

Figure 5: 2nd Generation Computer

CDT 04103

16

The Main Features of Second Generation

Use of transistors

Reliable in comparison to first generation computers

Smaller size as compared to first generation computers

Generated less heat as compared to first generation computers

Consumed less electricity as compared to first generation computers

Faster than first generation computers

Still very costly

A.C. needed

Supported machine and assembly languages

CDT 04103

17

Third Generation 1965-1970.

The computers of third generation used integrated circuits (IC’s) in place of transistors

A single IC has many transistors, resistors and capacitors along with the associated circuitry

The IC was invented by Jack Kilby.

This development made computers smaller in size, reliable and efficient

In this generation remote processing, time-sharing, multi-programming operating system were used

CDT 04103

18

Figure 5: 3rd Generation Computer

CDT 04103

19

The Main Features of Third Generation

IC used

More reliable in comparison to previous two generations

Smaller size

Generated less heat

Faster

Lesser maintenance

Still costly

A.C needed

Consumed lesser electricity

Supported high-level language

CDT 04103

20

Fourth Generation 1971-1980

The computers of fourth generation used Very Large Scale Integrated (VLSI) circuits.

VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation

Fourth generation computers became more powerful, compact, reliable, and affordable.

As a result, it gave rise to personal computer (PC) revolution

In this generation time sharing, real time, networks, distributed operating system were used

CDT 04103

21

All the high-level languages like C, C++, DBASE etc., were used in this generation

Figure 6: 4th Generation Computer

CDT 04103

22

The Main Features of Fourth Generation

VLSI technology used

Very cheap

Portable and reliable

Use of PC’s

Very small size

Pipeline processing

No A.C. needed

Concept of internet was introduced

Great developments in the fields of networks

Computers became easily available

CDT 04103

23

The Period of Fifth Generation 1980-Till Date

In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components

This generation is based on parallel processing hardware and AI (Artificial Intelligence) software

AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings.

CDT 04103

24

All the high-level languages like C and C++, Java,.Net are used in this generation.

AI includes

Robotics

Neural Networks

Game Playing

Development of expert systems to make decisions in real life situations.

Natural language understanding and generation

CDT 04103

25

Figure 7: 5th Generation Computer

CDT 04103

26

The Main Features of Fifth Generation

ULSI technology

Development of true artificial intelligence

Development of Natural language processing

Advancement in Parallel Processing

Advancement in Superconductor technology

More user friendly interfaces with multimedia features

Availability of very powerful and compact computers at cheaper rates

CDT 04103

27

Some Computer Types of This Generation

Desktop

Laptop

Notebook

Ultra Book

Chrome Book

CDT 04103

28

Computer is made up by hardware and software

HARDWARE

Hardware is the term used to describe the physical components of the system; the system unit (system box), monitor, keyboard, mouse, etc and is controlled by software.

It includes

Keyboard

Mouse

Monitor(Screen)

Central Processing Unit CPU)

System unit

Random Access Memory(RAM)

CDT 04103

29

Figure 8: Diagram of computer parts

CDT 04103

30

SOFTWARE

Software is another name of a program or programs.

The purpose of software is to convert data (unprocessed facts) into information (processed facts)

Software programs consist of the step-by-step instructions that tell the computer how to do its work or set of instruction which tell computer what to do

CDT 04103

31

In order computer physical part (hardware) to work properly there must be software. Software is set of instruction which tell computer what to do

There are two types of software

These are

System software and

Application software

CDT 04103

32

System Software

System software consists of programs that control the operations of a computer and its devices

System software serves as the interface between a user, the application software, and the computer’s hardware.

One type of system software is the operating system

Before application software can be run, the operating system, which contains instructions that coordinate the activities among computer hardware devices, must be loaded from the hard disk into the computer’s memory

CDT 04103

33

Application Software

Application software consists of programs designed to perform specific tasks for users.

Application software can be used as a productivity/business tool; to assist with graphics and multimedia projects; to support home, personal, and educational activities and to facilitate communications.

Specific application software products is called program and are available from software vendors.

CDT 04103

34

FUNCTIONS OF MAJOR PARTS OF A COMPUTER

Keyboard

Keyboard is an input device, partially modelled after the typewriter keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches

After punch cards and paper tape, interaction via teletype-style keyboards became the main input device for computers

CDT 04103

35

MOUSE

Computer’s mouse controls a graphical mouse pointer or mouse cursor on the screen.

When you move the mouse around by rolling it on your desk, the pointer on the screen moves in a similar manner

Roll the mouse left, and the pointer moves left; roll it in circles, and the pointer mimics that action

CDT 04103

36

BASIC MOUSE OPERATIONS

Point: When you’re told to “point the mouse,” you move the mouse on the desktop, which moves the mouse pointer on the screen to point at something interesting (or not).

Click: A click is a press of the mouse button — one press and release of the main button, the one on the left.

This action makes a clicking sound, which is where this maneuverer gets its name.

CDT 04103

37

Clicking is often done to select something or to identify a specific location on the screen.

Right-click: This action is the same as a click, although the right mouse button is used to get more commands.

Double-click: This one works just like the single click, although you click twice in the same spot — usually, rather rapidly.

This is most commonly done in Windows to open something, such as an icon

Both clicks must be on (or near) the same spot for double-click to work

CDT 04103

38

Drag: The drag operation is done to graphically pick up something on the screen and move it.

To do that, you point the mouse at the thing you want to drag, press and hold the mouse’s button (which “picks up” the object), and then move the mouse to another location

When you move the mouse (and keep the button down), the object moves

To release, or drop, the object, release the mouse button

CDT 04103

39

SPEAKERS

This is output device which use to convert electrical energy into sound

It consist essentially a thin flexible sheet called diaphragm that is made to vibrate by electrical signal from amplifier

CDT 04103

40

CENTRAL PROCESSING UNIT (CPU)

CPU is also called a processor, significantly impacts overall computing power and manages most of a computer’s operations

This is the component that actually executes instructions

The CPU contains

Control unit

Arithmetic / logic unit (ALU)

CDT 04103

41

Control unit directs and coordinates most of the operations in the computer

For every instruction, the control unit repeats a set of four basic operations called the machine cycle:

Fetching the instruction or data item from memory

Decoding the instruction into commands the computer understands

Executing the commands, and, if necessary

Storing, or writing the result to memory

CDT 04103

42

Arithmetic/logic unit (ALU) performs the execution part of the machine cycle. Specifically, the ALU carries out three operations:

Arithmetic operations – performing calculations, which include addition, subtraction, multiplication, and division

Comparison operations – comparing data items to determine if the first item is greater than, equal to, or less than the other item

Logical operations – working with conditions and logical operators such as AND, OR, and not

CDT 04103

43

Monitor

This is sometimes called screen or visual display unit.

This is an output device for electronic visual display on computers.

It allow user to see the data which entering into a computer and results after processing the data

Hard disk drive

Is a non- is a non-volatile storage device for digital data.

This means permanent storage

Hard disk is used to store all programs used by computer permanently and it is within the system

CDT 04103

44

Random access memory (RAM)

RAM is a form of computer data storage

It enables computer to store at least temporarily data and programs.

RAM is often associated with volatile types of memory

This means that its contents are lost when the computer is turned off

In general, memory (RAM) is fast and short-term

CDT 04103

45

Read-Only Memory (ROM)

Read Only Memory is a storage medium that is used with computers and other electronic devices

As the name indicates, data stored in ROM may only be read; it is either modified with extreme difficulty or not at all

ROM is mostly used for firmware updates

A simple example of ROM is the cartridge used with video game consoles

CDT 04103

46

Printer

This is an output device which allows user to view results in paper page

Uninterrupted Power Supply (UPS)

Is an electrical apparatus that provides emergency power to load when the input power source fail

Power supply

It is the component that supplies power to the other components in a computer system

Scanner

It is the device which is used to convert hardcopy materials to softcopy form

CDT 04103

47

Backup refers to the copying and archiving of computer data so it may be used to restore the original after a data loss event.

The verb form is to back up in two words, whereas the noun is backup

Data Backup is the result of copying or archiving files and folders for the purpose of being able to restore them in case of data loss

CDT 04103

48

Data loss can be caused by many things ranging from computer viruses to hardware failures to file corruption to fire, flood, or theft

As part of a data backup plan, you should consider the following

What data (files and folders) to backup

What compression method to use

How often to run your backups

What type of backups to run

What kind of media on which to store the backups

Where to store the backup data for safekeeping

CDT 04103

49

WHAT DATA SHOULD I BACK UP?

In general, you should back up any work or data that can’t be replaced easily.

Some examples are

word processing documents,

spread sheets,

databases (for financial data),

customer data, and

personal files such as pictures, music files and emails

CDT 04103

50

What Compression Method Should I Use?

You can use Best method compression with any or your backups.

This will insure that your Zip files will be as small as possible.

If you have a preferred compression method or if you would like the Zip files to be created more quickly, you have the option to choose a different method.

CDT 04103

51

HOW OFTEN SHOULD I RUN MY BACKUPS?

The frequency to run your backups depends on how often the data changes.

Business data that changes frequently may need daily or hourly backups

Data that changes every few days might use a weekly or even monthly backup

For some data, you might run your backup whenever you make a change

CDT 04103

52

WHAT KIND OF MEDIA SHOULD I USE AND WHERE SHOULD I STORE MY BACKUPS?

You can store your backup files on any file storage media you have.

The most common examples for a home user would be an additional local hard drive, an external hard drive, optical discs (CDs, DVDs, or Blu-ray discs), or flash drives.

A best practice for storing backups is to keep a copy of the backup files on-site (in your home or office) for easy access and a copy off-site in case of fire, flood, or other damage to your location which could damage or destroy the on-site backup copy.

CDT 04103

53

Types of Backup Equipment

MAGNETIC TAPE

Magnetic tape has long been the most commonly used medium for bulk data storage, backup, archiving, and interchange.

Tape has typically had an order of magnitude better capacity/price ratio when compared to hard disk, but recently the ratios for tape and hard disk have become a lot closer.

Some new tape drives are even faster than modern hard disks.

CDT 04103

54

HARD DISK

The capacity/price ratio of hard disk has been rapidly improving for many years.

This is making it more competitive with magnetic tape as a bulk storage medium.

The main advantages of hard disk storage are low access times, availability, capacity and ease of use.

The main disadvantages of hard disk backups are that they are easily damaged, especially while being transported (e.g. for off-site backups), and that their stability over periods of years is a relative unknown.

CDT 04103

55

OPTICAL STORAGE

Recordable CDs, DVDs, and Blu-ray Discs are commonly used with personal computers and generally have low media unit costs.

However, the capacities and speeds of these and other optical discs are typically an order of magnitude lower than hard disk or tape.

CDT 04103

56

SOLID STATE STORAGE

Also known as flash memories, thumb drives, USB flash drives, Compact Flash, Smart Media, Memory Stick, Secure Digital cards.

These devices are relatively expensive for their low capacity in comparison to hard disk drives, but are very convenient for backing up relatively low data volumes.

CDT 04103

57

REMOTE BACKUP SERVICE

As broadband Internet access becomes more widespread, remote backup services are scenarios such as fires, floods, or earthquakes which would destroy any backups in the immediate vicinity along with everything else.

There are, however, a number of drawbacks to remote backup services.

First, Internet connections are usually slower than local data storage devices.

CDT 04103

58

Secondly, users must trust a third party service provider to maintain the privacy and integrity of their data, although confidentiality can be assured by encrypting the data before transmission to the backup service with an encryption key known only to the user

CDT 04103

59

FLOPPY DISK

During the 1980s and early 1990s, many personal/home computer users associated backing up mostly with copying to floppy disks. However, the data capacity of floppy disks failed to catch up with growing demands, rendering them effectively obsolete.

gaining in popularity.

Backing up via the Internet to a remote location can protect against some worst-case

CDT 04103

60

LCDs

Printer

Un-interrupted Power Supply (UPS)

HPLC Machines

X-Rays Machines

Ultra sound

Public Addressing (PA) System

CDT 04103

61

Printer UPS

Ultrasound HPLC

CDT 04103

62

AP