23-12-2017, 10:17 AM
FUNCTIONAL UNITS OF COMPUTERS
*Input Unit
*Central Processing Unit
*Output Unit
INPUT UNIT AND OUTPUT UNIT’
*Device which receives data for processing are called input device.
*An input device converts input information into suitable binary code form acceptable to a computer.
Input Output devices
*Major Input Devices - Keyboard, Mouse, Light pen, Joystick, Scanner, Track ball, Microphone, Digital Camera, Touch screen, Barcode Reader, Optical Mark Reader (OMR), Magnetic Ink Character Recognition (MICR)
*Major Output Devices - Monitor, Printer, Projector, Sound card, Speaker, Video card, Plotter, Head phone
KEYBOARD
Keys on keyboard
*Alpha numeric keys - letters and numbers
*Punctuation keys - comma, period, semicolon etc.
*Special keys - Function keys, arrow keys, caps lock key. etc.
*The number of function keys on keyboard
Ans : 12
*The largest key on the keyboard
Ans : Space bar
*The key placed at the top left comer of the keyboard
Ans : Escape key (Esc key)
*The Primary input device
Ans : Keyboard
*The Primary output device
Ans : Monitor
ASCII
*Standard which is used to convert a keystroke to its corresponding bit
Ans : ASCII
*ASCII - American Standard Code for Information Interchange
*Normally ASCII has 7 - bit code characters.
*An 8 bit character encoding commonly used in IBM mainframe operation systems
Ans : EBCDIC
*EBCDIC - Extended Binary Coded Decimal Interchange Code
Ans : 256 (0-255)
