Input, Output and Storage Devices

Topic 1 A Level computer science

Input Device

hardware components that allow users to interact with a computer system by entering data

Output Device

Hardware components that receive information from a computer system and present it to the user in a comprehensible form

List some Input Devices

• keyboard: press keys to input text and commands

• mouse: allows user to navigate computer screen/ click on items

• touchscreen: allow users to interact with device

• scanner: digitises physical documents or images by converting them into a format that the computer can process

• game controller: allow you to control game characters

• webcam: captures video input - used for video conferencing

• graphics tablet: allows artists and designers to draw and sketch directly onto a computer

List some Output Devices

• monitor: displays visual output from computer, including text, images and videos

• printer: produces a hard copy of digital documents or images

• speakers: output audio from computer, such as music, sound effects, or voice

• headphones: output audio

• braille display: outputs braille

• Virtual reality: provides immersive visual and audio output

optical

• read from and written to using lasers

• binary information is represented by portions of the disc which either reflect or scatter incident laser light

• recessed portions are pits - 0/ flat portions are lands -1

optical devices

• CD: compact disc - use optical technology to store small quantities of information - used for audio files, text, digital images

• DVDs: digital versatile disc - have higher storage capacity than CDs, making them suited to storing digital videos which require more storage space than audio files or photos

• Blu-Ray: more than 5x as much storage than traditional DVDs - useful for high resolution films

Optical factors

CD disadvantages:

• can be easily damaged by scratched

• limited storage capacity

• low cost

• high portability

• relatively slow transfer speeds

• varieties of CD:

• — CD-R: can only be written to once

• — CD-RW: can be written to more than once

• — CD-ROM: written to during production and can then only be read from

Magnetic

• store information magnetically

• represent binary info using polarised and unpolarised magnetic states

• two states represent 1 and 0 - allowing any information to be represented in binary form

Magnetic Devices + factors

Hard Disk Drives:

• high capacity - 500GB to 5TB

• low cost per GB

• rotating magnetic platters at high speeds under read/write head to access any part of the platter

• moving parts means low portability

• moving parts means low durability - susceptible to damage from shocks or falls