These are the physical aspect of the computer that you see and touch. There are three basic hardware components viz; input/output, central processing unit, and auxiliary hardware.
1. Input is any data or instructions you enter into the memory of a computer. Once input is in memory, the CPU (Central Processing Unit) can access it and process the input into output.
Four types of input are data, programs, commands and user responses:
- Data is a collection of unorganized facts that includes words, numbers, pictures, sounds and videos. A computer manipulates and processes data into information, which is useful.
- A program is a series of instructions that tells a computer how to perform the tasks necessary to process data into information. Programs respond to commands issued by users. Programs are kept in storage media such as a floppy disk, hard disk, CD-ROM or DVD-ROM.
A user response is an instruction you issue to the computer by replying to a question posed by the computer program. An example can be Do you want to save the changes you made? If your answer is Yesto this question, the program saves your changed file on a storage device.
Output is data that has been processed into a useful form called information. This means a computer processes input into output. Computers generate several types of output, depending on the hardware and software being used and the requirements of the user. You may choose to display or view this output on a monitor, print it on a printer, or listen to it through speakers or a headset. Four common types of output are text, graphics, audio and video.
- Text consists of characters that are used to create words, sentences and paragraphs. A character is a letter, number, punctuation mark, or any other symbol that requires one byte of computer storage space.
- Graphics are digital representations of nontext information such as drawings, charts and photographs. Graphics can also be animated, giving them the illusion of motion. Animation is created by displaying a series of still images in rapid sequence.
- Audio is music, speech, or any other sound. Recall that sound waves such as the human voice are analog. To store such sounds, a computer converts the sounds from a continuous analog signal into a digital format.
- Video consists of images that are played back at speeds that provide the appearance of motion. Video is often captured with a video input device such as a video camera or VCR. Most video signals are analog: however, some video devices record the video images digitally.
They are hardware devices that send information into the CPU. Without any input device, a computer would simply be a display device and not allow users to interact with it, much like a TV. Below is a listing of different types of computer input devices.
- The Keyboard
One of the main input devices used on a computer, a PC’s keyboard looks very similar to the keyboards of electric typewriters, with some additional keys. Today most users use the QWERTYstyle keyboards. Below is a graphic illustration of where each of the keys is on a U.S. QWERTY style keyboard.
A US QWERTY Keyboardlayout
Below is a graphic of the Saitek Gamers’ keyboard with indicators pointing to each of the major portions of the keyboard?
A Gamers Keyboard
Anatomy Of The Keyboard
Keyboard is among the input devices we use to enter data into the computer memory. The computer keyboard resembles the typewriter keyboard. It has 101/102 keys divided into five groups:
- Typing keys
- Special keys
- Function keys
- Dedicated cursor keys
- Numeric key pad
When a key is pressed its corresponding character would appear on the screen.
These are the keys that contain the 26 letters of the alphabet
The function keys are labeled from F1-F12 of the keyboard and they are used for different purposes. These have different application programs depending on the software in use. E.g. in Microsoft windows F1 is generally for help, F2 for Renaming of an item, et.c they can also be combined with other keys to perform a specific function e.g. ALT + F4 closes a window.
This key cannot be used alone, it need to be paired with other keys to perform certain operation e.g. it can be used to enter upper and lower case character.
This key also doesn’t perform any function when used alone; it is used in conjunction with other keys on the keyboard to generate internal code on the system e.g.
|1.||Ctrl + A||to select all characters|
|2.||Ctrl + B||To Bold selected text|
|3.||Ctrl + C||To Copy selected item|
|4.||Ctrl + E||To move an item to the centre of a page|
|5.||Ctrl + F||To find a character within a page (s)|
|6.||Ctrl + I||To Italize characters|
|7.||Ctrl + L||To move an item to the left side of a page|
|8.||Ctrl + N||This starts a new window|
|9.||Ctrl + O||To open an existing document|
|10.||Ctrl + P||To printout a page|
|11.||Ctrl + R||To move an item to the right|
|12.||Ctrl + S||To save an item|
|13.||Ctrl + U||To underline characters|
|14.||Ctrl + V||To paste|
|15.||Ctrl + W||To close a window|
|16.||Ctrl + X||To Cut|
|17.||Ctrl + Z||To undo an action.|
The Alternate Key
It is also paired with other keys to give command e.g. ALT + F4 to close a window
Caps lock Key
It is a toggle key that is On/Off key. It is used to change characters from lower case to upper case and vice-versa. When the caps lock key light is on all the characters are in the upper case and when the light is off the characters return to the lower case.
The Enter Key
This key is similar to the carriage in typewriter it is also called return key or carriage. When it is pressed it will command the computer to execute a certain action
This key is used to create space from left to the right
This key deletes characters from right to the left of the cursor.
This key is similar to the typewriter tab. The key shifts the cursor eight spaces to the right of current position.
The Escape Key (Esc)
In MS-DOS it means the current line would be deleted. But as other meanings when pressed in other programs. It may exit the current activity and return to the previous, it also enables you to abandon error condition and resume to the activity prior to it.
Ctrl + Tab
Pressing of these two keys will move the cursor to the right.
Numeric Key Pad
These keys are Located at the right hand side of the keyboard. The numeric mode is activated when the numlock key which is a toggle switch is pressed
Its function is deleting character from the left of the cursor to the right.
Page Up And Page Down Keys
Page up key moves the screen up by one page while page down moves the screen down by one page.
Home And End Keys
Home keys move the cursor to the up left position of the screen while end key moves the cursor to the end of the line.