AQA GCSE COMPUTER SCIENCE PAPER 2
WRITTEN ASSESSMENT 2026 EXAM REVIEW
COMPLETE QUESTIONS AND ANSWERS
◉ Run-Time Error. Answer: Might or might not cause a program to
crash at some point, but it will not prevent it from running. The
error will not become apparent until the program is executing.
◉ Trace Tables. Answer: A tool used for checking that a program will
behave as you intend it to by examining the value of each variable as
it changes. They are usually used to resolve logical errors.
◉ Try Catch Block. Answer: The program is told, rather than to
execute some code, to try to execute some code. This would then
provide an alternative set of instructions to be followed in case the
attempt fails.
◉ Bug. Answer: In a piece of software, is a fault or error of some
kind that prevents the software from working as it should.
◉ Debugging. Answer: The process by which bugs are removed.
There are tools available to developers to help identify bugs, break
points and variable watch. Trace tables and the use of try catch
blocks would be used alongside these tools.
,◉ Break Points. Answer: Inserted at a line of source code at which
execution will pause (break). The developer can then examine the
state of the program at this particular point in execution. Multiple
break point can be set throughout the code, which is a useful feature
as it allows the developer to view the execution of the program in
something resembling slow motion.
◉ Stepping. Answer: Moving from one break point to another,
essentially watching program execution in slow motion.
◉ Variable Watch. Answer: This feature allows the developer to keep
track of a variable or expression. This tool allows you to track the life
of a variable expression to see if it is correctly manipulated by the
program.
◉ Computer System. Answer: A combination of hardware (physical
components) and software (the programs) working together to
provide a solution to a problem. They are important because they
play a part in almost every aspect of human life: in commerce, health
care, education and communication. It is important that they are
reliable (do what is expected of them) and robust (provide
resistance against failure and remain available).
, ◉ Four Key Elements Computer Systems Consist of. Answer: Input
devices - Are used to get data onto the system, Keyboard, mouse,
magnetic tripe reader, light pen, OMR, scanner, OCR, sensors.
Output devices - Which present data in a human-friendly form,
Monitor, speakers, printer, servomechanism.
Storage devices - Used to contain data.
Processor - Follows instructions and performs calculations.
◉ Hybrid Devices (Both Input and Output). Answer: Touch screens
because you input data by touching the screen and the device
outputs data by displaying it on the screen.
Games controllers, you input by using the controls and they output
by vibrating.
◉ The CPU and the Two Main Components. Answer: A component
that performs calculations and fetches and executes program
instructions. There are two main components: The Arithmetic Logic
Unit (ALU) - carries out calculations and numeric functions such as
comparing two numbers together to see which is the largest.
The Control Unit - Responsible for retrieving data and instructions
from the correct location in memory and executing those
instructions.
◉ Buses. Answer: How the processor communicates with other
parts of the system. Buses are wires or collections of wires that
WRITTEN ASSESSMENT 2026 EXAM REVIEW
COMPLETE QUESTIONS AND ANSWERS
◉ Run-Time Error. Answer: Might or might not cause a program to
crash at some point, but it will not prevent it from running. The
error will not become apparent until the program is executing.
◉ Trace Tables. Answer: A tool used for checking that a program will
behave as you intend it to by examining the value of each variable as
it changes. They are usually used to resolve logical errors.
◉ Try Catch Block. Answer: The program is told, rather than to
execute some code, to try to execute some code. This would then
provide an alternative set of instructions to be followed in case the
attempt fails.
◉ Bug. Answer: In a piece of software, is a fault or error of some
kind that prevents the software from working as it should.
◉ Debugging. Answer: The process by which bugs are removed.
There are tools available to developers to help identify bugs, break
points and variable watch. Trace tables and the use of try catch
blocks would be used alongside these tools.
,◉ Break Points. Answer: Inserted at a line of source code at which
execution will pause (break). The developer can then examine the
state of the program at this particular point in execution. Multiple
break point can be set throughout the code, which is a useful feature
as it allows the developer to view the execution of the program in
something resembling slow motion.
◉ Stepping. Answer: Moving from one break point to another,
essentially watching program execution in slow motion.
◉ Variable Watch. Answer: This feature allows the developer to keep
track of a variable or expression. This tool allows you to track the life
of a variable expression to see if it is correctly manipulated by the
program.
◉ Computer System. Answer: A combination of hardware (physical
components) and software (the programs) working together to
provide a solution to a problem. They are important because they
play a part in almost every aspect of human life: in commerce, health
care, education and communication. It is important that they are
reliable (do what is expected of them) and robust (provide
resistance against failure and remain available).
, ◉ Four Key Elements Computer Systems Consist of. Answer: Input
devices - Are used to get data onto the system, Keyboard, mouse,
magnetic tripe reader, light pen, OMR, scanner, OCR, sensors.
Output devices - Which present data in a human-friendly form,
Monitor, speakers, printer, servomechanism.
Storage devices - Used to contain data.
Processor - Follows instructions and performs calculations.
◉ Hybrid Devices (Both Input and Output). Answer: Touch screens
because you input data by touching the screen and the device
outputs data by displaying it on the screen.
Games controllers, you input by using the controls and they output
by vibrating.
◉ The CPU and the Two Main Components. Answer: A component
that performs calculations and fetches and executes program
instructions. There are two main components: The Arithmetic Logic
Unit (ALU) - carries out calculations and numeric functions such as
comparing two numbers together to see which is the largest.
The Control Unit - Responsible for retrieving data and instructions
from the correct location in memory and executing those
instructions.
◉ Buses. Answer: How the processor communicates with other
parts of the system. Buses are wires or collections of wires that
