IGCSE ICT chp 2

The whole chapter in flashcards cuz im smart and ima top

Keyboards

-most common data entry method

-connected to a computer by wires

-is virtual in tablets and phones

-when key is pressed, its converted to a digital signal for the computer

-may cause RSI (repetitive strain injury)

How does a keyboard work?

-membrane/circuit at the base of the keys

-when key is pressed it makes contact with bottam conductive layer

-CPU can now determine which key has been pressed

-CPU refers to an index file to identify which character the pressed key represents

Use of keyboards

-Input of data into applictaion softwares

-Typing in commands to the computer

Advantages of keyboards

-Fast entry of new text into doc

-Well known method

-Easy to use

-Easier to verify with the source as the data is being entered

Disadvantages of keyboards

-Can difficult to use if someone has broken hand/wrist

-slower compared to direct data entry

-takes up desk space

Numeric keypads

-is used to enter numbers only (some may be alphanumeric)

Use of numeric keypads

-ATMs (Automated teller machine)

-Phones when dialing numbers

-POS (Point of sale terminals) in case barcode reader fails

-Chip/PIN devices when paying with credit/debit cards

-Fast entry of numeric data in spreadsheets

Advantages of numeric keypads

-Faster than standard keyboards when entering numeric data

-Its more easy to carry since its smaller

Disadvantages of numeric keypad

-Small keys making it harder to input data

-order of number on keypad isnt intuitive

Mouse

-example of pointing device

-user controls the position of a pointer on the screen by moving it

-may have 2 buttons + scroller

Robust

A device/system’s ability to handle unexpected errors, exceptions and failures

Optical mouse

-movement detected by reflected light rather than position of moving ball

-doesnt catch dust since there arent moving parts

cordless mouse

-transmits signals to a USB wireless receiver plugged into the computer

Advantages of optical mouse

-more robust

-doesnt catch dust

-unlike the older type of mouse this doesnt skid on surfaces so u dont lose control of the pointer

Uses of mouse

-open, close, minimise software

-grp, move, delete files

-image editing(control position and size of image)

-control position of pointer on the screen allowing the user to select from a menu

-can scroll

Advantages of mouse

-faster at choosing options than keyboard

-quick way of navigating through applications/internet

-requires lesser desk space

Disadvantages of mouse

-Difficult to operate for ppl with broken hand/wrist

-Easy to damage

-can get clogged cuz of dirt and dust

-needs a flat surface to operate