IGCSE Computer Science Paper 1 Definitions Worksheet: 3.2 Input and Output Devices and 3.3 Data Storage (Modules 293–303)
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Key terms
Write what each term means, in your own words.
1
feedback loop
2
data first, then sensor
3
suitable sensor
4
inputs and outputs
5
primary storage
6
volatile memory
7
ROM
8
RAM vs ROM
9
RAM and ROM
10
secondary storage
Answer Key
IGCSE Computer Science Paper 1 · Modules 293–303 · Student wording will vary for definitions
1feedback loop — A sensor sends readings to a microprocessor, which compares them with a stored value and signals an actuator, such as a heater, to act. This repeats continuously.
2data first, then sensor — Each sensor captures one type of data, so identify the data first (e.g. moisture in soil, humidity in air), then name the sensor that measures it.
3suitable sensor — The sensor that measures the physical quantity a system needs, e.g. light for street lamps or pressure for a car park. Justify it with 'because'.
4inputs and outputs — A complete system uses input devices or sensors to capture data and output devices or actuators to deliver results, each chosen to suit the task.
5primary storage — Memory the CPU can access directly, so it is fast. It is made up of RAM (temporary, holds running programs and data) and ROM (permanent, holds start-up instructions).
6volatile memory — Memory that loses its contents when the power is off, like RAM. Non-volatile memory, like ROM and SSDs, keeps its data without power.
7ROM — Read only memory: non-volatile primary storage whose contents are fixed. It keeps the start-up (boot) instructions, so data stays when power is off. Also used in embedded devices.
8RAM vs ROM — RAM is volatile, read/write and holds running programs; ROM is non-volatile, read only and holds start-up instructions. RAM is larger.
9RAM and ROM — ROM holds the start-up instructions that survive power-off. RAM holds the changing operating system, programs and data in use. A computer needs both to start up and to run.
10secondary storage — Non-volatile storage the CPU cannot access directly. It keeps data permanently, even when power is off. Data is copied to RAM before use. Types: magnetic, optical, solid-state.