Parts of computer and their uses

 

Main Parts of Computer and Their Uses

The standard computer consist of a monitor, a keyboard, a mouse an the system unit. One can attach accessories such as printers and scanners by means of ports. Increasingly in the workplace, computers are connected to printers and other computers by means of a network.

Figure 1 Computer System Hardware

The Monitor

                

This is the Visual Display Unit (VDU). There are various technologies for the display unit, cathode ray tube (CRT) or Liquid Crystal Display (LCD) or electron luminescent screens or the projector. The monitor or screen displays your work. Facing it down reduces reflected glare form room lights. This refection may affect your sight. Monitors come in different size. The (most important) size of the monitor is measured diagonally on the screen ( in inches ). Based on this, the monitors range in sizes of 12”, 14”, 15”,17”,19”,21”,29”, etc Monitors are also characterized by the flatness of their screen. The flatter and the wider screens are usually the better.

The system box or computer console

       

  The system box is where all the computations that the computer performs take place inside are the CPU processor, the motherboard, the hard disk, any network or sound cards, memory chips (RAM), printer ports (at the back) and the drive bays for floppy disks, Zip disks or CDs. Outside the casing are the power buttons (ON/OFF and Restart) with some additional facilities like the casing USB ports., Webcams, etc.

The Keyboard (Pressing)

      

   This is the basic input device. It is one of the ways you can tell the computer what to do. It consists of the standard typewriter keys as well as a numeric keypad and function keys. You can use it to give the computer commands, name folders and files, and type text in word processing documents. The keyboard is made of three main categories of keys with each used for a different purpose.

1.   Character Keys: These comprise of letters, numbers and the symbols. They are used to insert/display readable characters on the screen which his equivalent to the keystroke pressed.

Letters: a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z

Numbers Symbols:  0, 1, 2, 3, 4, 5, 6, 7, 8, 9

Accent	`	Dash/Minus	-	Equal	=	Opening Square Bracket	[	Closing Square Bracket	]
Backslash	\	Semi-Colon	;	Single-Quote		Pipe	|	Greater than	>
Less than	<	Comma	,	Period	.	Forward Slash	/	Question mark	?
Tilde	~	Exclamation Mark	!	At	@	Pound	#	Dollar	$
Dollar	$	Percent	%	Caret	^	Ampersand	&	Asterisk	*
Asterisk	*	Opening Parenthesis	(	Closing Parenthesis	)	Underscore	_	Plus	+
Opening Curly Bracket	{	Closing Curly Bracket	}	Colon	:

 

2  Action Keys:      

                    These are not used to type anything, instead they cause an action. Escape, Tab, Caps Lock, Shift, Control, Alt, Backspace, Enter, Windows, Win Menu, Print Screen, Scroll Lock, Pause Break, Number Lock, Insert, Home, Page Up, Delete, End, Page Down, Power, Sleep, Wake up, Up Arrow, Left Arrow, Right Arrow, Down Arrow,  and space Bar.

3. Application- Dependent Keys: 

                             These are called function keys. They are F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11 and  F12. Although the F1 key is usually used to get help while working in Microsoft Windows, the use of the other keys various from one application to another. Eventually, the application you use will give you instructions on what to do and how to use the function keys.

Key Combinations

    Some keys can be combined to produce uppercase letters or to access the upper symbols of some keys (i.e. the shift and control keys). Keys are also combined for many other reasons. In some situations, you have to press keys simultaneously, which means that you may be expected to press two or more keys at the same time, or almost at the same time. In some other situations, you may have to press and release one key, followed by another.

 Shortcuts

        A shortcuts is a quick action you ask a program to perform when you press one particular key or a combination of keys. Some shortcuts ar universal or almost, that is, the computer responds regardless of what application is running. Some other shortcuts depend on what you have on your screen. Some shortcuts already know to the computer (as part of the operating system ). Most other shortcuts are set by the programmer of the particular application you are using. Yet some application  allow you to create own shortcuts. Some shortcuts are readily obvious and can be seen from the main menu of the application . some other shortcuts are either part of Microsoft windows (and can be applied in your program ) or are not easily displayed , you might have to search the Help documentation of the program you are using.

The Mouse (clicking and Dragging )

                                            

This is another input device used to move a small white arrow pointer the cursor (but the shape will change depending on the context in which the mouse is being used) on the screen. By pointing and clicking you can carry out commands. The computer may ask you to verify that you are sure to rename a file, by clicking on the ‘OK’ button. A mouse is primarily made of three parts: the buttons, the handling area, and the sensor  (rolling object or light). There are either one, two or three mouse wheel on top of the middle button called the Scroll Button.

To use the mouse, the first decision you make is to know which of your two hands you will be using to handle the mouse. By default, the mouse is configured to work for the right hand. If you are left-handed, the settings can be changed to suit your needs:

Start  → Control Panel → Double-click Mouse → On the Buttons Tab, Check the Switch Primary and Secondary Buttons check box.

You can also change the cursor from the default Up-Left Pointing to another  but you should know that this is best determined by the computer as this varies from program to program. To change, click the Pointer’s Tab. Also click the other tabs to review the different properties.

Note: The expression “by default” means “if everything is not (yet) changed from the original or normal settings”.

Figure 2 : Mouse Properties Dialog Box

         The tip of the mouse pointer must be positioned on the item you want to use (Pointing). To select and item, point to the item and click once (selection-Left Clicking). Double-clicking (Left  button) on an icon invokes a command or launches an application. Dragging an item (icon or other object) from one location to another, position the mouse pointer on the item, click and hold the mouse buttons (left, right) down, and move the item top the new location. Right clicking (right button) invokes a shortcut (contextual) menu that contains all the actions that are related to the item,. Some application, namely programs used to manipulate text (they are called word processors). Allow you to triple-click.

On windows machines, there is a left and right mouse button. Most time you use the left mouse button (if you are right-handed). On some newer Macs, the same feature can be used with their single mouse button by holding down the Control key as you click an item on the screen.

The Peripherals

All the parts we have reviewed so far are usually required for the computer to function. Some other parts , not required, can also be connected to the computer complement it. A peripheral is an object attached to the computer to help it perform some necessary assignments none of the other parts can handle. In most scenarios, no peripheral is required but nowadays, it is unusual for a computer not to have any peripheral at all. The most used peripherals are the printer, a digital camera, a scanner, a projector, an external drive (such as an external CD burner for an old computer), etc.

Disk Size Conversion Chart (Bits, Byes, Kilobytes, Megabytes and Gigabytes)

Bit- Binary digit:-a single elements in the computer memory that can store either 1 or 0

Word – 1Byte, 2 Byte or 4 Byte depending on the machine. Generally computer word length is giving in bits; hence we have 8bit, 18bit or 32bit microprocessor computer.

Table: Computer Storage Devices Unit Conversion

Unit	Equivalent to
1 Byte	8 Bits
1 Kilobyte (KB)	1024 Byte
1MB	1024 KB=1024,000Byte
1GB	1024MB=1024,000 Byte