CAMBRIDGE IGCSE COMPUTER
SCIENCE EXAM STUDY SET
QUESTIONS WITH CORRECT ANSWERS
Web browser - answer-software that allows a user to display a webpage on their screen
- they interpret html code and show the result
Actuator - answer-used in many control operations involving sensors and adc/dacs.
Electromagnetic device eg. Motor that outputs result of sensor operation
Loudspeaker - answer-output device that produces sound using voltages at different
levels which vibrate a cone in speaker housing
Led - answer-used for backlighting a monitor/tv - they are thin, produce a white light,
and do not require much power
Volatile - answer-memory that loses its contents when the power is off eg. Main memory
Non-volatile - answer-memory that doesn't lose its contents when the power is off e.g.
Hard disk
Off-line storage - answer-storage that can be physically moved away from a device and
stored somewhere else e.g. Cd, usb stick, dvd
Magnetic media - answer-secondary storage with mechanical parts which move over
the surface to read and write data magnetically e.g. A hard disk, tape or floppy disk
Assembly language - answer-code that is specific to a particular hardware, but needs to
be translated into machine code before it can run
Machine code - answer-the binary code that is specific to a machine and does not need
translating in order to run
Translator - answer-program that changes higher level language into machine code
Compiler - answer-this translates hll into machine code. Once it has done this, the
program can be used multiple times without translating it again
Free software - answer-software that is free to run, copy, change or adapt, and share
with friends, family or colleagues.
Gigabyte (gb) - answer-1024 megabytes. 2 to the power of 30 bytes.
,Html - answer-hypertext mark-up language. Used to write and develop webpages to
present text. Uses tags.
Terabyte (tb) - answer-1024 gigabytes. 2 to the power of 40 bytes.
Lossless image compression - answer-find groups of repeating data. Records the data
once and the number of times it was repeated.
Lossless text compression - answer-finds patterns in original text. Encodes each pattern
in a dictionary
Png - answer-lossless picture file format that uses alpha channel to keep transparent
backgrounds.
Parity bit - answer-set to 1 or 0. Sent with a byte of data to make the total number of 1s
odd or even for each byte.
1kb (kilobyte) - answer-1,024 bytes (2¹⁰ bits)
1mb (megabyte) - answer-(2²⁰ bits)
1gb (gigabyte) - answer-(2³⁰ bits)
1tb (terabyte) - answer-(2⁴⁰ bits)
1pb (petabyte) - answer-(2⁵⁰ bits)
A - answer-10
B - answer-11
C - answer-12
D - answer-13
E - answer-14
F - answer-15
Parity check - answer-uses parity bits. Odd parity / even parity agreed between sender
and receiver. If it is not the agreed number, an error has occurred.
Arq (automatic repeat request) - answer-uses acknowledgement and timeout. If
acknowledgement isn't sent back to sender before the timeout occurs, message
automatically resent.
, Checksum - answer-additional value sent at the end of a data block. When block is
about to be transmitted, additional value calculated and then transmitted. Value
recalculated at the end to make sure they match. If they don't match, an error has
occurred.
Echo check - answer-data sent to and from another device twice. Sender compares 2
sets of data, if the sets of data are different, an error has occurred.
Mac address - answer-a number that uniquely identifies a device on the internet. Often
refers to network card. Rarely changed.
Mac address - answer-number which uniquely identifies a device - 1st half =
manufacturer, 2nd = device itself - made up of 6 groups of hex digits
Rom - answer-memory that is hard coded at time of manufacture. Stores start-up
programs, bios and bootstrap
Secondary memory/storage - answer-long-term, non volatile storage media e.g. Hard
disk
Virtual memory - answer-part of the hard disk that is programmed to work as an
extension of main memory
Optical media - answer-secondary storage that is read using lasers e.g. Cd, dvd
Solid state/flash memory - answer-secondary storage with no moving parts; used in
memory sticks, cameras and phones
High level language - answer-portable language designed with the programmer in mind
- it is easy to understand and debug, but it needs to be translated in order for a
computer to understand it
Low level language - answer-language relating to specific architecture and hardware of
a particular device - can refer to assembly lang or machine code
Interpreter - answer-this translates hll into machine code one line at a time.
Assembler - answer-this translates assembly language into machine code. Once it has
done this, the machine code can be used multiple time without translating it again.
Spyware/key logging software - answer-hardware or software that can be used to
monitor key presses and gain information.
Freeware - answer-software that a user can download for free from the internet, but
they are not allowed to edit the source code
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