Introduction of Computer

FUNDAMENTAL OF COMPUTER

What is computer?

                Computer is an advanced electronic machine. Which can processes both numerical and non-numerical information. The term “computer” derived from the Latin Language “Comptare” which means calculate. Similarly, in English language calculator was introduced. Computer originated with a huge size and extreme processing capabilities. Computer has become very powerful device to aid the development in the field of data processing and research. Therefore, it has become almost indispensable in modern technologies. It is a totally user dependent device. It has no its own brain. Computer calculates the 100% correct result according to the user’s guide. Computer does not have life in it. It operates on electricity.

Parts of the computer:

1. Power supply: Volt guard, Stabilizer, UPS.
2. Input Device: Mouse, Keyboard.
3. CPU (Central Processing Unit):

i.                     ALU (Arithmetic and Logic Unit).

ii.                   CU (Control Unit).

4. Out put: Monitor (Screen), Printer.
5. Memory Device (Attach to the CPU):

a. Primary Memory: RAM (Random Access Memory).

  ROM (Read Only Memory).

b. Secondary Memory: Hard Disk, Pen Drive, Compact Disk or DVD.

Essential Features of the computer:

1. Hardware.
2. Software.
3. Human ware.

Hardware and Software:

                The parts of computer what we see and touch are called hardware. They are Keyboard, Mouse, Monitor, CPU, Printer, etc.

                The computer application or program what is written in machinery language is called Software. Software actually means the non physical part of computer, which are recorded in computer’s disk. Software is something like our soul. To run or to apply software on computer needs hardware. The computer application or software in Ms-Dos, Ms-word, Ms-excel, etc.

Types of software: Normally, there are two types of software:

1. System software.

2. Application software.

System Software:

                The software required for running user program is known as system software. System software is the collection of the program written for computer, which allows the user to develop and run program. The system software is provided along with the computer itself and is stored in ROM. They are: Dos, Windows, etc.

Application software:

                The software written for special purpose in a language is known as application software. These programs perform certain task with respect to related program. Ms-word, Ms-excel, Ms-Power Point, etc. are the example of application software.

Human ware:

                Man also related to the computer system. So the user (who use computer) is known as Human ware because without man computer can’t work itself.

Types of Computer:

                Up to now, there is no clear cut classification of computer. Basically, computers are classified on the basis of different groups. They are:

1.       On the basis of work:

1. Analog Computer:

Seismograph is an example of analog computer. Speedometer in cars and motorcycles is another example of the analog device. Such a change measurement device reference to the other is called analog computer. The device that are used to measure the size of stone in kidney, mental disease, diagnostics with the photographs are analog computers.

2. Digital Computer:

Digital computers are mostly used in the preparation of reports, results and graphic representations.

3. Hybrid Computer:

They are used in big industries, scientific research institutions, airplanes, etc.

2.       On the Basis of Size:

1. Mainframe computer:

Mainframe computer are systems that offer faster processing speeds and greater storage capacity that the others. In a huge room (May be 100 ft. long and 50 ft. wide), about 100/200 worker are needed. In Nepal, there are two mainframe computers:

a)       IBM 1401: It is the first computer which is brought in Nepal. It was brought in 2028 B.S.

b)       ICL 2950/10: It is the second computer which is brought in Nepal. It was brought in 2038 B.S. and it was brought from England.

2. Mini Computer:

Mini computers are medium in size, which means, it is bigger than Micro Computer and smaller than Mainframe. It may require a smaller in room than that of the mainframe. The device used in the minis is smaller in size. At a time, at least 50 operators can work with the single CPU. For data processing, programming, desktop publishing, etc.

3. Micro Computer:

Micro Computers are based on microchips. Micro computers are also called Home computer or personal computers. Micro computers are extensively used at homes and offices. Today, its capabilities and speed computer. Micro computers can do one task at a time, but mainframe computer can do several tasks at the same time.

i.                     Desktop Computer.

ii.                   Laptop Computer (Briefcase size).

iii.                  Palmtop Computer.  

3.       On the Basis of Brand:

i.                     IBM PC.

ii.                   IBM Compatible.

iii.                  Apple/Macintosh.

4.       On the Basis of Model:

i.                     AT Computer.

ii.                   XT Computer.

iii.                  P/S2 Computer.

5.                   On the Basis of Processing speed:

i.                     PC/XT (640 KB 4.77 to 8 MHz).

ii.                   PC/AT (640 KB -8 to 10 MHz).

iii.                  PC/AT 286 (1.2 MB -10 to 16 MHz).

iv.                  PC/AT 386 (4 MB -16 to 25 MHz).

v.                   PC/AT 486 (4 MB -25 to 33 MHz).

vi.                  Pentium I.

vii.                Pentium II.

viii.               Pentium III.

ix.                  Pentium IV.

Note:

XT = Extended Technology.

AT = Advanced Technology.

Computer Devices:

                You have seen that an animal has a head, legs, ears, eyes, nose, mouth, etc. similarly a computer must also have some parts, without it can’t work. Sometimes computers are connected with some devices. Every part had a particular function. Some of these devices are listed below.

1. Input and Output device: Keyboard, Mouse are input and Monitor, Printer are Output.

2. Keyboard: The keyboard has numerical key (0-9), alpha key (A-Z), function key (F1-F12) and operating keys (Ctrl, Alt, Delete). The keyboard looks like similar to the typewriter.

3. Esc key: You can press Esc to quit a task you are performing.

4. Caps Lock key: The caps lock is a key on a computer’s keyboard. When it is pressed, all the letters typed will be in capitals or upper case.

5. Shift key: The shift key is a key on a computer keyboard. It is used to tell the computer that a capital or upper case letter is required.

6. Ctrl key: The ctrl key is a key on a computer keyboard. It is use with others keys to send commands or produce special characters on the VDU. It is use to copy.

7. Alt key: The Alternate key is a key on a computer keyboard. The alternate key is use in combination with other keys. It is help down while another key or a command is typed in.

8. Function key: Each of the twelve keys labeled F1 to F12 is called the function key. When any of the keys is pressed, it performs a certain task. F1 is pressed to display help information.

9. Enter key: It is the key, which is pressed to start a new line in a word processor. It is also pressed to enter information into spreadsheet. To press enter is the same as to click on ok in a dialogue box.

10. Backspace key: It is the key on your computer which is use to delete the character or the cursor. Backspace means to move the cursor in a backward direction.

11. Delete key: It is key that is pressed to remove characters. Delete is pressed remove the space or character to the position which is to the right of the cursor.

12. Arrow key: These are the keys, which are used for moving the cursor in different directions. That is up, down, right and left around your screen.

13. Mouse: It is an input device connected to the CPU of the computer. It is used to move cursor on screen. Mouse can be used to make figure or copy on screen. Mouse may have one or two click button. In some cases even three click buttons with the movement of the ball. The cursor can be moved on the screen, open the menu or any other function can be performed. It is a small plastic box with buttons on top and a ball or Sensor light underneath. When the ball or sensor light is moved over a mouse pad. The ball rolls or light move and a marker appear on the visual display unit. Pressing the buttons on the mouse gives instruction to the computer.  

14. Monitor: Monitor is the display device connected with the CPU. It is also called Visual Display Unit (VDU). It is just like the TV screen. When you press any character on the keyboard, the pressed character is displayed on the screen.

                All monitors (screen) are not of same type. There are different in size and color. A very tiny blinking material is seen on the monitor, when you opened word program called cursor. By the movement of the cursor, you can see in which point of monitor you are working. Generally, monitors are 80 character wide and 25 lines rows.

15. Printer: Printer is hard output device. It attached to the main machine or CPU. Early printers were very slow and noisy. There are different types of printers such as: Dot Matrix & Laser etc.

16. Volt Guard: Volt guard is the device used to supply power to the computer. It lies between the computer and the main power supply point of the room.

17. CPU (Central Processing Unit): CPU means central processing unit. It is the most important part of the computer that does all the working or all processing is called processor. It is called the processing or CPU instead of processor because it is the main processing unit of the computer. The CPU is the heart of computer.

18. ALU (Arithmetic and Logic Unit): ALU takes care of all the mathematical and logical functions done by the computer.

19. CP (Control Power): This is actually the busy part in a computer. This unit controls all the other parts of the computer like the input and output device and go processor.

20. Memory: Memory is the place where data and instruction are stored temporarily or permanently. This is the most important unit of the computer. This determines the power and capacity of a computer. The memory of computer is divided into two parts.

A) RAM (Random Access Memory): RAM is a read and writes memory. This is the memory part which is your program, DOS and software you have used it. This memory is erasable. As the electricity goes off or you shut down the computer without saving you work, every thing in the RAM will be erased, the RAM size of each computer may different. You can increase the size of RAM.

B) ROM (Read Only Memory): ROM is the permanent memory.  Information cannot be written into this memory after manufacture. Information is permanently stored in the ROM, when it is manufacture.

21. Pen Drive: It is a pocket data traveler. It is used to carry your document, program, software etc. It size is from 512 MB to 1TB. It is smaller than Hard disk and greater then CD or DVD.

22. Hard Disk: Hard disk is used to store media. Each computer consist hard disk (without hard disk computer can’t work). Hard disk is packed in a sealed metallic material. They connected with a controller card called hard disk drive controller card. The hard disk interface is through a cable. Huge number of data can be stored in this type of storage media. It is necessary for every disk to be kept safe from virus, which may damage not only data, but also the hard disk. Hard disk have different capacity of memory of hard disk is measured in Giga Bytes.

23. Boot: Booting the computer basically, the process of starting your computer is called booting. In facts, the process of loading Dos-sys files into the computer memory from disk (e.g.: Floppy disk or Hard disk) is known as booting.

Types of booting:

a) Cold Boot: Where a computer is turned on, the computer reads RAM and searches for Dos-sys, files from disk drives (C :) as soon as it finds the sys. Files, those files are brought into computer memory from C: drive, this is known as cold boot.

b) Warm Boot: If you are working with your computer and you wish to reboot or restart the computer you press Ctrl + Alt + Delete keys at the same time. Computer stays powered on during the process and searches for Dos-sys. Files and loads these file into the RAM. This is known as warm boot.

How to start your computer?

1. Switch on your power switch.

2. Switch on you screen switch.

3. Wait for some time, you will come to windows 2005 desktop screen.

How to shut down your computer?

1. Click on start button.

2. Select shut down and click it.

3. Then appears a shut down dialogue box.

4. Choose Shut down.

5. Click on ok.