CIE IGCSE COMPUTER SCIENCE: KEY
TERMS EXAM GUIDE QUESTIONS AND
ANSWERS
Actuator - Answer-An output device that changes an element of the physical world,
usually a motor, light or buzzer.
Control System - Answer-Uses feedback from a sensor to control a physical process
and can run without user input for some time.
Feedback - Answer-When the computer measures the effect of a process that it
controls, usually through the use of input sensors.
Input Device - Answer-Converts data into digital signals that can be processed by the
computer.
Primary Storage - Answer-Consists of RAM and ROM.
Output Device - Answer-Converts the information inside the processor into a useful form
outside the computer.
RAM - Answer-Volatile read-write storage inside the CPU.
Read-only - Answer-Data and instructions can be taken from here by the processor. It
cannot be used to store new data.
Read-write - Answer-Data and instructions can be taken from and written to here by the
processor.
ROM - Answer-Non-volatile storage used to store the start-up instructions for the
computer.
Storage Device - Answer-Retains data and instructions in digital form.
Secondary Storage - Answer-Non-volatile storage outside of the processor.
Volatile - Answer-Data is lost if electricity is lost.
Non-volatile - Answer-Data is retained even if electricity is lost.
Optical Storage Media - Answer-Stores and retrieves data from a digital disc with the
aide of a laser.
, Solid State Storage Media - Answer-Stores and retrieves data from a digital drive using
electricity. Very fast to access data because it does not have any parts that physically
move.
Magnetic Storage Media - Answer-Stores and retrieves data from a digital drive using
positive and negative electronic charges.
Cloud Storage - Answer-Using an internet service to store data.
CD-R/DVD-R - Answer-Optical storage media that can be recorded to once only. The
storage media is blank when first purchased.
CD-RW/DVD-RW - Answer-Optical storage media that can be written to many times.
The storage media is blank when first purchased.
CD-ROM/DVD-ROM - Answer-Optical storage media that cannot be written to. The
storage media contains data when first purchased.
Off-line Storage - Answer-Similar to secondary storage but outside of the computer. For
example a portable hard drive or magnetic tape.
Resistive Screen - Answer-Two layers that conduct electricity. Inexpensive but can be
easily damaged.
Capacitive Screen - Answer-Uses conductive strips either side of a transparent sheet, at
right angles so that the strips make a grid. An electronic charge on the screen changes
when touched.
Infra-red Screen - Answer-Two sets of invisible beams projected at right angles across
the screen, making a grid.
ALU - Answer-Is part of the CPU. It passes data through logic circuits. The circuits
change the data using the rules of logic and arthimetic.
Bus - Answer-A short communication link which joins up two parts of the processor.
Control Unit - Answer-Manages the flow of data through the processor; and from the
processor to peripherals.
Fetch-Execute Cycle - Answer-First the CPU takes data and instructions from memory.
Next the data is changed according to the instructions.
Logical Deduction - Answer-A method of working out whether conclusions are true. You
start out with some known facts, and you work out the logical conclusions.
TERMS EXAM GUIDE QUESTIONS AND
ANSWERS
Actuator - Answer-An output device that changes an element of the physical world,
usually a motor, light or buzzer.
Control System - Answer-Uses feedback from a sensor to control a physical process
and can run without user input for some time.
Feedback - Answer-When the computer measures the effect of a process that it
controls, usually through the use of input sensors.
Input Device - Answer-Converts data into digital signals that can be processed by the
computer.
Primary Storage - Answer-Consists of RAM and ROM.
Output Device - Answer-Converts the information inside the processor into a useful form
outside the computer.
RAM - Answer-Volatile read-write storage inside the CPU.
Read-only - Answer-Data and instructions can be taken from here by the processor. It
cannot be used to store new data.
Read-write - Answer-Data and instructions can be taken from and written to here by the
processor.
ROM - Answer-Non-volatile storage used to store the start-up instructions for the
computer.
Storage Device - Answer-Retains data and instructions in digital form.
Secondary Storage - Answer-Non-volatile storage outside of the processor.
Volatile - Answer-Data is lost if electricity is lost.
Non-volatile - Answer-Data is retained even if electricity is lost.
Optical Storage Media - Answer-Stores and retrieves data from a digital disc with the
aide of a laser.
, Solid State Storage Media - Answer-Stores and retrieves data from a digital drive using
electricity. Very fast to access data because it does not have any parts that physically
move.
Magnetic Storage Media - Answer-Stores and retrieves data from a digital drive using
positive and negative electronic charges.
Cloud Storage - Answer-Using an internet service to store data.
CD-R/DVD-R - Answer-Optical storage media that can be recorded to once only. The
storage media is blank when first purchased.
CD-RW/DVD-RW - Answer-Optical storage media that can be written to many times.
The storage media is blank when first purchased.
CD-ROM/DVD-ROM - Answer-Optical storage media that cannot be written to. The
storage media contains data when first purchased.
Off-line Storage - Answer-Similar to secondary storage but outside of the computer. For
example a portable hard drive or magnetic tape.
Resistive Screen - Answer-Two layers that conduct electricity. Inexpensive but can be
easily damaged.
Capacitive Screen - Answer-Uses conductive strips either side of a transparent sheet, at
right angles so that the strips make a grid. An electronic charge on the screen changes
when touched.
Infra-red Screen - Answer-Two sets of invisible beams projected at right angles across
the screen, making a grid.
ALU - Answer-Is part of the CPU. It passes data through logic circuits. The circuits
change the data using the rules of logic and arthimetic.
Bus - Answer-A short communication link which joins up two parts of the processor.
Control Unit - Answer-Manages the flow of data through the processor; and from the
processor to peripherals.
Fetch-Execute Cycle - Answer-First the CPU takes data and instructions from memory.
Next the data is changed according to the instructions.
Logical Deduction - Answer-A method of working out whether conclusions are true. You
start out with some known facts, and you work out the logical conclusions.
