IGCSE Computer Science Paper 1 Definitions Worksheet: 3.1 Computer Architecture and 3.2 Input and Output Devices (Modules 240–251)
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Date:
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Key terms
Write what each term means, in your own words.
1
machine code
2
embedded system
3
general-purpose computer
4
fetch-decode-execute
5
keyboard
6
optical mouse
7
microphone
8
digital camera
Answer Key
IGCSE Computer Science Paper 1 · Modules 240–251 · Student wording will vary for definitions
1machine code — The binary (0s and 1s) form of instructions that the CPU can run directly. Each instruction has an opcode and an operand. Programs must be translated into it to run.
2embedded system — A computer system built into a larger device to perform one dedicated function, usually running a fixed program. Examples: a washing machine controller or a microwave timer.
3general-purpose computer — A computer, such as a PC or laptop, that can do many different jobs by running different programs, and the user can install new software.
4fetch-decode-execute — A full-mark CPU answer uses exact names for registers, buses and units, and gives the fetch, decode and execute steps in order, e.g. PC to MAR, then MDR, then CIR.
5keyboard — An input device where pressing a key completes a circuit. The controller identifies the key and sends its character code to the computer, so text and commands can be entered.
6optical mouse — An input device with an LED or laser under it that lights the surface while a sensor takes rapid images to track movement and move the pointer. It has no ball.
7microphone — An input device that turns sound waves into an analogue electrical signal, which an ADC converts to digital data so the computer can record or process voice.
8digital camera — Input device: a lens focuses light onto an image sensor of light-sensitive cells; each cell becomes a pixel of digital data, stored as an image file. More pixels give more detail.