Cambridge IGCSE Computer Science
questions and answers 2025/2026 latest
update
HTTP - hypertext transfer protocol - answera set of rules which must be followed when transferring files
across the internet
URL - uniform resource locator - answerused to find/identify a webpage on the internet 1. webserver
name 2. file name 3. protocol
web browser - answersoftware that allows a user to display a webpage on their screen - they interpret
html code and show the result
actuator - answerused in many control operations involving sensors and ADC/DACs. Electromagnetic
device eg. motor that outputs result of sensor operation
loudspeaker - answeroutput device that produces sound using voltages at different levels which vibrate
a cone in speaker housing
LED - answerUsed for backlighting a monitor/tv - they are thin, produce a white light, and do not require
much power
CCFL - answerOld technology used for backlighting - took time to warm up, and produced yellow-ish
lighting + required a lot of power
volatile - answermemory that loses its contents when the power is off eg. main memory
non-volatile - answermemory that doesn't lose its contents when the power is off e.g. hard disk
off-line storage - answerstorage that can be physically moved away from a device and stored
somewhere else e.g. CD, USB stick, DVD
,SRAM - answertype of RAM that has 'flip flops' to hold each bit of memory. Does not need constant
refreshing.
magnetic media - answersecondary storage with mechanical parts which move over the surface to read
and write data magnetically e.g. a hard disk, tape or floppy disk
program - answerour way of telling a computer what to do, how to do it, and when to do it
assembly language - answercode that is specific to a particular hardware, but needs to be translated into
machine code before it can run
machine code - answerthe binary code that is specific to a machine and does not need translating in
order to run
translator - answerprogram that changes higher level language into machine code
compiler - answerthis translates HLL into machine code. Once it has done this, the program can be used
multiple times without translating it again
UPS - answeruninterruptable power supply
cracking - answerediting source code with malicious intent
firewall - answerthis examines traffic between a user's computer and the internet by checking what
is/isn't allowed and blocking traffic that does not meet certain criteria
proxy server - answerthis filters web traffic, keeps the IP address secret, and, using a cache, speeds up
access to websites that have been visited before
TLS - Transport Layer Security - answerthis is a form of secure data transmission made up of 2 layers: the
record protocol, and the handshaking protocol. It is very secure and fairly new, and can make use of
,session caching, which improves performance. It involves many complicated encryption algorithms.
prevents third party hacking into communication between web server and the user's computer.
session caching - answerthis is used in TLS to avoid using too much computer time; TLS is able to
attempt to resume an existing session, which increases speed.
Denial of Service (DoS) attack - answerattempting to prevent a user from accessing part of a network
(usually the server); this is usually temporary, but may be very damaging, or a big security breach.
overloads web traffic by sending thousands of requests.
free software - answersoftware that is free to run, copy, change or adapt, and share with friends, family
or colleagues.
CSS - answerCascading Style Sheet. Controls presentation of page. Enable multiple pages or elements on
a page to be changed in one go.
Gigabyte (GB) - answer1024 megabytes. 2 to the power of 30 bytes.
HTML - answerHyperText Mark-up Language. Used to write and develop webpages to present text. Uses
tags.
Terabyte (TB) - answer1024 gigabytes. 2 to the power of 40 bytes.
Lossless image compression - answerFind groups of repeating data. Records the data once and the
number of times it was repeated.
Lossless text compression - answerFinds patterns in original text. Encodes each pattern in a dictionary
PNG - answerLossless picture file format that uses alpha channel to keep transparent backgrounds.
MIDI - answerA set of instructions for digital instruments to play synthesised sounds. Musical Instrument
Digital Interface.
, .WAV - answeruncompressed music files
.FLAC - answerlossless compressed music files
Parity bit - answerSet 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) - answer1,024 bytes (2¹⁰ bits)
1MB (megabyte) - answer(2²⁰ bits)
1GB (gigabyte) - answer(2³⁰ bits)
1TB (terabyte) - answer(2⁴⁰ bits)
1PB (petabyte) - answer(2⁵⁰ bits)
A - answer10
B - answer11
C - answer12
D - answer13
E - answer14
F - answer15
questions and answers 2025/2026 latest
update
HTTP - hypertext transfer protocol - answera set of rules which must be followed when transferring files
across the internet
URL - uniform resource locator - answerused to find/identify a webpage on the internet 1. webserver
name 2. file name 3. protocol
web browser - answersoftware that allows a user to display a webpage on their screen - they interpret
html code and show the result
actuator - answerused in many control operations involving sensors and ADC/DACs. Electromagnetic
device eg. motor that outputs result of sensor operation
loudspeaker - answeroutput device that produces sound using voltages at different levels which vibrate
a cone in speaker housing
LED - answerUsed for backlighting a monitor/tv - they are thin, produce a white light, and do not require
much power
CCFL - answerOld technology used for backlighting - took time to warm up, and produced yellow-ish
lighting + required a lot of power
volatile - answermemory that loses its contents when the power is off eg. main memory
non-volatile - answermemory that doesn't lose its contents when the power is off e.g. hard disk
off-line storage - answerstorage that can be physically moved away from a device and stored
somewhere else e.g. CD, USB stick, DVD
,SRAM - answertype of RAM that has 'flip flops' to hold each bit of memory. Does not need constant
refreshing.
magnetic media - answersecondary storage with mechanical parts which move over the surface to read
and write data magnetically e.g. a hard disk, tape or floppy disk
program - answerour way of telling a computer what to do, how to do it, and when to do it
assembly language - answercode that is specific to a particular hardware, but needs to be translated into
machine code before it can run
machine code - answerthe binary code that is specific to a machine and does not need translating in
order to run
translator - answerprogram that changes higher level language into machine code
compiler - answerthis translates HLL into machine code. Once it has done this, the program can be used
multiple times without translating it again
UPS - answeruninterruptable power supply
cracking - answerediting source code with malicious intent
firewall - answerthis examines traffic between a user's computer and the internet by checking what
is/isn't allowed and blocking traffic that does not meet certain criteria
proxy server - answerthis filters web traffic, keeps the IP address secret, and, using a cache, speeds up
access to websites that have been visited before
TLS - Transport Layer Security - answerthis is a form of secure data transmission made up of 2 layers: the
record protocol, and the handshaking protocol. It is very secure and fairly new, and can make use of
,session caching, which improves performance. It involves many complicated encryption algorithms.
prevents third party hacking into communication between web server and the user's computer.
session caching - answerthis is used in TLS to avoid using too much computer time; TLS is able to
attempt to resume an existing session, which increases speed.
Denial of Service (DoS) attack - answerattempting to prevent a user from accessing part of a network
(usually the server); this is usually temporary, but may be very damaging, or a big security breach.
overloads web traffic by sending thousands of requests.
free software - answersoftware that is free to run, copy, change or adapt, and share with friends, family
or colleagues.
CSS - answerCascading Style Sheet. Controls presentation of page. Enable multiple pages or elements on
a page to be changed in one go.
Gigabyte (GB) - answer1024 megabytes. 2 to the power of 30 bytes.
HTML - answerHyperText Mark-up Language. Used to write and develop webpages to present text. Uses
tags.
Terabyte (TB) - answer1024 gigabytes. 2 to the power of 40 bytes.
Lossless image compression - answerFind groups of repeating data. Records the data once and the
number of times it was repeated.
Lossless text compression - answerFinds patterns in original text. Encodes each pattern in a dictionary
PNG - answerLossless picture file format that uses alpha channel to keep transparent backgrounds.
MIDI - answerA set of instructions for digital instruments to play synthesised sounds. Musical Instrument
Digital Interface.
, .WAV - answeruncompressed music files
.FLAC - answerlossless compressed music files
Parity bit - answerSet 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) - answer1,024 bytes (2¹⁰ bits)
1MB (megabyte) - answer(2²⁰ bits)
1GB (gigabyte) - answer(2³⁰ bits)
1TB (terabyte) - answer(2⁴⁰ bits)
1PB (petabyte) - answer(2⁵⁰ bits)
A - answer10
B - answer11
C - answer12
D - answer13
E - answer14
F - answer15
