Introduction To Computer

        Introduction To Computer

Computer

            Computers are revolutionizing every field of science. We hear on the radio and see on    the television about the computer advancement every day. Computers are applied in agricuture, medicine, researches, astronomy, chemistry, biology,  etc. The use of computers is increaqsing  day-by-day. With the aid of computers students can learn at home, musicians can compose music, writers can write and engineers can design.

1.1 Computer Study

        Computer study deals with the features of computers, their uses, limitations, variations and how the computer components are made. The depth of the study of computer is unlimited. You will study some features of computers, their uses  and software that are necessary to assist saily work. You will also study programming features using BASIC ( Beginner's All purpose Symbolic Instruction Code).

1.2 Computer Literacy

              Literacy means knowing how to read and write. Computer literacy is related to the study and use of computers, their features, limitations, speed, accuracy, etc. Some of the features you will study in sections below are:

·        Computer's capabilities and limitations,

·        How to use computers in different fields,

·        How the software is developed, and

·        The effects of computer on society and education.

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1.3 Understanding the Computer

        In order to understand the computer you have to study many books. But concise definition of computer is:a computer is an electronic device used to manipulate the data and instructions so that it processes and gives desired result. This device has input section, processing sectioand output section. A computer is a dull machine. Unless instructions are given to the computer, it does nothing and computer does one task at a time. The processing speed, i.e., working speed of the computer is very high. It works with electric pulses at the speed of light.

1.4 Capabilities and Limitations of Computers

   A computer cannot do anything you desire. People may think that a computer is capable of launching a rocket, so it should be able to cook food too. Computerised

equipment can cook food, but the computer in your laboratory is not made for that purpose. Some computers are specially designed for particular task. For example, the computer used to launch a rocket is specially made for that purpose

   The capabilities and limitations are discussed below:

   (a) Speed

   (b) Accuracy

   (c) Storage

   (d) Diligence

   (e) Versatility

   (f) Reliability

(a) Speed: Computers worl in millionth or billionth of a second. The speed of the computer is very high. Though the computer does one task at a time, the speed of computer makes it appear that it does many tasks at a time. The time required to process and execute the result I measured in fraction of a second. The fractions of a second are given below.

(b) Accuracy: Computers are very accurate. A computer has a tiny chip inside it which does not wear out. The chips have integrated circuits on which electrons (electric pulses) flow. The instructions is wrong the result will bw ambiguous. Such an ambiguity is termed as GIGO (Garbage-In-Garbage-Out). Therefore, the data and instruction must be accurate and specific to the computer.

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(c) Storage: Computers can store huge number of data. Data (sing: datum) are the relevant information given to the computer for processing. The date of birthe, name, class, section are some examples of data. The computers use Hard Disks which have big storage capacity. the tape drive and microfiche are other examples of storage devices wgich have huge data storage capacity.

(d) Diligence: computers do not get tired when a task is performed repeatedly. It is a human-made machine and it does repeated tasks. In the quality control and process control, repeated tasks are performed by the computers.

 (e) Versatility: Computers perform data processing at a great speed. The data may be of any kind. It performs processing and gives the result of that processing to a suitable device. A computer perform data processing, spreadsheet calculations and word processing. Thus, computers are versatile in processing tasks.

(f) Reliability: Computers are very much reliable. The components inside the microprocessors do not wear out. The electric pulses move at the rate of speed of light inside the integration does not malfunction.

Computers have Limitations

          The limitations of computer can be summarized as follows:

·   Computers do not have their own thinking capacity.

·   Computers always need stored program for their functionality.

·   Computers need electrical power to operate.

·   An operator is necessary to give instructions to the computer.

1.5 Appearance of Computer

        There are numerous manufacturers that produce different of computer. But the computers are mainly manufactured in two principles: Apple/Macintosh and IBM (International BUsiness Machines).

       Apple/Macintosh computers are mostly used in wordprocessing and spreadsheet calculations. These computers are different from IBM computers in architectural designs.

        IBM computers are based on a different principle and architectural design. IBM computers are manufactured by IBM Corporation, USA. The computers which are in use mostly are IBM computers. Compatible means that the principles exist together. IBM compatible computers can perform all the tasks that an IBM computer does.  IBM compatible computers are mostly used in data processing, programming, quality control, process control, education, games, word processin, accountancy, etc. You will study the features of IBM compatible computers in this book. Every computer has disk drives. The disks are used as storage device. There may be a hard disk in a personal computer. The two external drives of the computer are : Drive A: and Drive B:. The hard disk is fixed inside the computer. Every computer needs two depending upon individual computer configuration.        All computers are not same in processing and speed capabilities. Some computers are very fast and some are slow in processing. A computer has a main chip or processor, commonly called microprocessor. The microprocessor has a serial number. The computers can be classsified on the basis of processors. Some microprocessors are listed below:

        Recent development in the manufacture of microprocessor is Pentium (P5) technology., which will be replaced by new technologies. The Central Processing Unit of the computer lies within the main processor or microprocessor. The computers may contain additional processor called co-processor which enables them to process complex mathematical tasks very fast. IN 80287 and 80387 respectively.

Disk Drives: There are two external disk drives: Drive A: and Drive B:. The internal disk drive of personal computer is commonly called Fixed Disk or Hard Disk. Hard disks are fixed inside the computer. Recent development over hard disks is exchangeable hard disks. They are less common but it is expected that they will overtake the place of fixed disks in microcomputer.

        A floppy disk may have a size 5 " × 5 " or 3 " × 3 ". The disk may be of high density or double density. The floppy disks are devided into different sectors and tracks. Newly purchased disk does not have any sectors or tracks. The disk is formatted so that it contains the sectors and tracks. The number of sectors and tracks determines the storage capacity of the disk. The number of sectors, tracks, and their capacity is given below.

1.6 The Computer System
        In a computer system, the data is fed through a suitable device. the device may be input device or storage media. THe data is processed by the processor and result of this processing will be displayed on the monitor or on a suitable output device such as printer or plotter. But sometimes, data given to the computer is wrong and the processing output will also be indesirable. Such a phenomenon is called Garbage-In-Garbage-Out (GIGO). The processing operation is performed by the processor inside the computer which is located on the motherboard. The general architect of input, processing and output is given below.

Fundamental Knowledge of Computer

      The computer uses microprocessor which has the capacity of using applications, formatting the documents and other manipulations, uses storage devices, graphics design and animation as well as artificial intelligence.

Working Principle of Computer

      The computer works on the principle of Input, Processing and Output.

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Input: The devices such as mouse, keyboard, microphone are used as input devices and the instructions are accepted by the computer.

Processing: The computer uses its main processor and supporting processor for analyzing and processing data and instructions.

Output: The computer generates the result of processing which is commonly known as output. The output of the processing is diplayed on the screen, printed or sent to the speaker.
Storage: The computer can store the data, instructions, intermediate results and final results of output on the stprage devices such as hard disk, RAM or optical discs.
      The computer's main processor has different sections to perform different tasks. These sections are:
       1. Arithmetuc and Logic Unit (ALU),
       2. Control Unit(CU), and
       3. Memory Unit.

1. Arithmetic and Logic Unit (ALU): the ALU performs the arithmetic operations and logical operations. The arithmetic operations involve the calculation of numbers such as addition, subtraction, multiplication or division whereas logical operations are comparison between the two data or conditions with the help of suitable operators such as greater than (>), smaller than (<), equal to (=), greater or equal to (>=). The arithmetic and logic section plays storage to arithmetic and logic section or vice-versa.
2. Control Unit (CU): The entire system of the computer gets the instructions, direction, selection, interpretation, execution of program, etc. This section does not process the data but the data and instructions are interpreted in the CU and the other components get the instructions from the Control Section.
3. Memory Unit: Memory Unit holds the data. The data is meant to be processed. This section has the responsibility of holding the data and instruction from the keyboard and Conrol section of the system. The intermediate results are also being held in this section.

1.7 Memory Characteristics

        Memory is the name for any part of computer that is made to store data. Early computers had vaccum tubes as the memory devices. The vaccum tubes were discovered by Lee De Forest in 1908. The advancement over vaccum tubes were the transistors which were discovered by a team led by William Shockley in 1948. The other members of the team were John Burden and Walter H. Brattain. A transistors functioned equal to 1000 vaccum tubes. Later on, transistors were replaced by integrated circuits. Intergrated circuits were developed by Jack Kilby and Robert Noyace in 1959. But its official authentication for marketing was given to Harwick Johnson of RCA in 1953. Integrated Circuits were called chips. The developments on the chips or integrated circuits are: LSI (Large Scale Integration) and VLSI (Very Large Scale Integration).

         Memory of computer is either volatile or non-volatile. The volatile memory is often called RAM (Random Access Memory). The other type of memory is permanent and is called ROM (Read Only Memory). That means RAM is erasable and ROM is not erasable.

(i) Read Only Memory (ROM): ROM (Read Only Memory) is the permanent memory. This type of memory chip stores programs permanently. The program stored in the ROM is called firmware. The recent advancement over ROM are: PROM (Programmable Read Only Memory). EPROM (Erasable and Programmable Read Only Memory), EEPROM (Electrically Erasable and Programmable Read Only Memory).

(ii) Random Access Memory (RAM): Random Access Memory (RAM) is a volatile memory. This is the memory part in which your program, DOS and software you have used fit. The RAM size of each computer may differ. You can increase the size of RAM above 640K which is called extended memory. 640K memory of the computer is base memory. When you switch on the computer, it reads the RAM space in the first place.

        Random Access Memory can be divided into two

major categories - the Static RAM (SRAM) and the Dynamic

RAM (DRAM). Static RAM has the power of storing data as

long as electrical power is given. As soon as the power is put

off, the data and instruction on the SRAM will be washed

away, which cannot be retrieved at all. The Dynamic RAM

holds data for a few milisecond and needs periodic refreshing.

The refresing usually performed from the main processor of the

system.

        Latest computers use new memory system. DDR1,

DDR2 and DDR3 are the latest development of Dynamic RAM

and they are extensively used in Pentium III and Pentium IV

computers.

1.8 Parts of a Computer System

        The basic requirement to install a complete computer system are:

         1. Volt Guard

         2. Central Processing Unit

         3. Monitor

         4. Keyboard

         5. Printer

 

     1. Volt Guard: Volt guard is the device used to supply poer to the computer. It lies between the computer and the main power supply point of a room. For a personal

computer, voltage regulator, autocut, voltage stabilizer or UPS (Uninterrupted Power Supply) are the most common. Uninterrupted Power Supply (UPS) supplies the power to the computer automatically when electrical power is cut off. This prevents the loss off data.

2. Central Processing Unit: The computer's main part is the CPU (Central Processing Unit). This section is primarily made of Arithematic Logic Unit, Control Unit and Main Memory (Storage Unit). The CPU lies inside the main machine or chassis of the computer. The CPU performs all the functions of processing, interpretation, control, etc. In the earlier section of this chapter, the individual sections of CPU have been discussed.

3. Monitor: Monitor is the display device connected with the CPU. It is also called Visual Display Uniy (VDU). Monitors were connectred to the CPU since 1964. The monitors display the data given and process result. It is like a TV screen which displays the characters and it has a cathode ray tube (CRT). The monitors of IBM and IBM compatible computers are tilted whereas the monitors of Apple/Macintosh are fixed. A small blinking material is seen on the monitor called 'cursor'. By the movement of the cursor you can see in which point of the monitor you are working.

Monitor

        All monitors are not of same type. There are various types of monitors classified on the basis of resolution. Some monitors have high resolution which can even display the pictures from a Video Cassette Recorder (VCR). The monitors need an interface card to control and send data from the CPU. The different typrs of display control cards are:

4. Keyboard: Keyboard is the main input device. All computers are attached with a keyboard. The data and instructions are given through the keyboard. When a key is pressed, the signal is interpreted and sent to the computer in the form of digital signal. These digital signals are interpreted, processed, or controlled by the main processor of the computer. The earky computers had 83 keys but most of the keyboards have 101 or 103 keys or even more.

Keyboard

5. Printer: Printer is the device which gives hard output. The device is attached to the main machine or CPU. Early printers were slow and noisy. But there are printers which give high quality of printing and yet they are very quite. Dot matrix printer, Laser printer and Daisy wheel printer are some types of printers. Some Dot Matrix printers print many lines in one minute and give high quality printing.
        Printers of microcomputers may have 9 pins, 18 pins or 24 pins. Generally a printer with higher number of pins give better quality of printed output. There are some laser printers in connection with the mainframe computers and minicomputers which can print 64000 lines per minute !

Printer

1.9 Some Terms of Computer
 
Data: The term data refers to fact or figure. They can be daily expenditure, information about game, numerical calculation, a document, etc.

Information: Information is the processed output. Sometimes, the information thus produced can be data for another processing procedure. The is meaningful to the user and computer. The marks obtained by a student, the division that you get in the examination are information.

Program: A program is set of instruction to the computer. The computer understands its own language. The computer's language is in binary digits. The programs are written using different programming languages such as C, C++ but they are finally converted in the binary format. The programs are designed for instructions.

Hardware: The physical part of the computer known as hardware. The hardware includes electronic components, connectivity wires, circuit on the motherboard or other devices, monitor, mouse, keyboard, etc.

Software: The software is another important component of computer. Computer cannot work without software. Every hardware is controlled by the software. Software is made for specific purpose.

 MAIN POINTS TO REMEMBER
Main Points To Remember:
1. Computers are used in every fiels. Some of the areas where computers are very successful are:
   business, banking, air-traffic, computer-based, education and training.            
2. Computer study is the study of computers, their features, use, limitations and how the components
   are made.
3. Computer literacy means knowing about the use of computers, their features, limitations, speed,
   accuracy, etc.
4. A computer is an electronic device used to manipulate data and instructions so that it processes
   and gives desired result.
5. The capabilities of computers are: speed, accuracy, storage, diligence, versatility and reliability.
6. Computers do not have their own thinking capacity and they need stored program to run.
7. IBM and IBM-compatible computers have similar technology whereas Apple/Macintosh has different
   technology.
8. A disk drive is a physical drive which can hols a diskette. The diskette contains data and program.
   The drive reads and writes data and program onto the disk.
9. A disk contains concentric circles called tracks and different zones called sectors.
10. The CPU has three sections: ALU, CU and MU.
11. The ALU performs the arithmetic and logical operations.
12. The control unit gives instructions, directions, selection, interpretation and execution of programs.
13. The memory unit holds the data. There are two types of memory: permanent menory and
    temporary memory.
14. RAM and ROM are examples of Primary memory. Secondary storage device such as hard disk,
    optical disk, floppy disk and represent secondary memory.
15. RAM is volatle; it loses its content as soon as electricity goes off. ROM holds the diagnostics of
    the computer and instructions called firmware.
16. The hard disks hold operating system software, programming software and application software.
17. A computer system is the integration of power supply unit, processing unit, input unit and output
    unit.
18. The monitor is softcopy output unit. The printer is hardcopy output unit.
19. A keyboard is an essential input device for desktop computer.

Full Forms:

     BASIC     =    Beginner's All purpose Symbolic Instruction Code             
     GIGO      =    Garbage-In-Garbage-Out          
     ALU       =    Arithmetic Logic Unit         
     CU        =    Control Unit                
     MU        =    Memory Unit        
     LSI        =    Large Scale Integration
     VLSI       =    Very Large Scale Integartion
     RAM       =    Random Access Memory
     SRAM      =    Static Random Access Memory
     DRAM      =    Dynamic Random Access Memory
     ROM       =    Read Only Memory
     PROM      =    Programmeable Read Only Memory
     EPROM     =    Eraseable and Programmeable Read Only Memory
     EEPROM   =    Electrically Eraseable and Programmeable Read Only Memory
     VDU        =    Visual Display Unit
     CRT        =    Cathode Ray Unit
     UPS        =    Uninterrupted Power Supply
     VCR        =    Video Cassette Recorder
     MDA        =    Monochrome Display Adaptor
     CGA        =    Coloured Graphic Adaptor
     MCGA      =    Multi-Colored Graphic Adaptor
     EGA        =    Enhanced Graphic Adaptor
     VGA        =    Video Graphic Array
     SVGA       =    Super Video Graphic Array