EDEXCEL IGCSE COMPUTER SCIENCE
GLOSSARY EXAM QUESTIONS WITH
COMPLETE ANSWERS
Abstraction - answer-the process of removing or hiding unnecessary detail so that only
the important points remain
Access control - answer-this decides which users have access to which data, and what
they are allowed to do with it
Agent - answer-a computer system that can interpret its environment ( through its
sensors ). It can act autonomously upon that environment ( through its effectors )
Algorithm - answer-a precise method for solving a problem. All instructions given to a
computer must be unambiguous or it won't know what to do.
Analogue - answer-using signals or information represented by a quantity ( e.g. An
electric voltage or current ) that is continuously variable. Changes in the information
being represented are indicated by changes in voltage. This method requires very
accurate sending and receiving systems.
Application programming interface ( api ) - answer-code that allows two programs to
communicate each other
Application software - answer-software that performs a task that would otherwise be
done by hand, perhaps a pen and paper
Arithmetic/logic unit ( alu ) - answer-the part of the cpu that performs calculations and
logic operations
Arithmetic operator - answer-an operator that performs calculation on two numbers
Arithmetic shift - answer-used for signed binary numbers. When performing a right shift,
the bits at the left are replaced by copies of the most significant bit
Array - answer-an organized collection of related values that share a single identifier
Ascending order - answer-this is arranging items from smallest to largest ( e.g. 1,
2 ,3 ,4, 5, 6, 7, or a, b, c, d )
Assembler - answer-translates the mnemonics of assembly language programs into
machine language instructions for the microprocessor to carry out
,Assembly language - answer-a low-level language written using mnemonics
Assignment statement - answer-the set .. To command is used to initialise variables in
pseudocode
Audit trail - answer-a record of activities that have taken place on a computer system.
This record is generated automatically and will record what has happened and who or
what made the change.
Authentication - answer-the process of providing to a computer system who you are
( e.g. Using a username and password )
Autonomous - answer-self-directed and acts without requiring any help or guidance.
Can choose its own goal and uses its experience to achieve it.
Back-up - answer-a copy of files in another location so that they are still available if the
original copy is damaged or lost. Backing up is the process of making a back-up copy.
Bandwidth - answer-the amount of data that can be carried on a network in a given
period of time
Binary - answer-information represented by only two values ( e.g. Voltage or no
voltage ; on or off ). There are no communication errors or misunderstandings because
there are no small differences
Binary digit ( bits ) - answer-the smallest unit of data that is represented in a computer.
It has a single binary value , either 1 or 0.
Binary prefix - answer-multiplies a unit by powers of 2
Binary shift - answer-an operation done on all the bits of a binary value in which they
are moved by a specific number of places to either left or right
Bit depth - answer-the number of bits used to encode the information from each sample.
Increasing the number of bits used increases the amount of detail contained in each
sample.
Block of code - answer-a grouping of two or more code statements
Bluetooth - answer-a protocol for the short-range wireless interconnection of mobile
phones, computers, and other electronic devices
Boolean - answer-something that can take only the values true or false ; named after
english mathematician george boole
, Brute force - answer-an algorithm design that does not include any techniques to
improve performance, but instead relies on computing power to try all possibilities until
the solution to a problem is found
Bug - answer-an error or flaw in a computer program
Built-in functions - answer-functions that are provided in most high-level programming
languages to perform common tasks
Bus - answer-a group of connections between devices in a computer
Bus width - answer-the number of wires that make up a bus. This determines the range
of binary numbers that can be communicated
Byte - answer-the basic combination of bits used to represent an item of information. A
byte typically consists of 8 bits
Cache - answer-a temporary data store so that the data can be accessed very quickly
when needed
Cache memory - answer-memory used to make up for the difference in speed between
two internal components
Cache miss - answer-when the data requested for processing by a component or
application is not found in the cache memory
Carbon footprint - answer-the amount of carbon dioxide an individual or organization
produces as a result of the energy they consume
Central processing unit ( cpu ) - answer-hardware device that carries out the processing
in a computer
Character set - answer-the defined list of characters recognised by a computer's
hardware and software
Checksum - answer-a technique for finding errors. A mathematical formula is applied to
the date and the resulting number value is tansmitted with the date. The recipient
computer applies the same formula to the received data. It then compares the
checksum sent with the date to the calculated checksum. If the checksums don't match,
the data is likely to have been corrupted. So, the recipient computer requests the data
again.
Ciphertext - answer-encrypted plaintext
Client-server network - answer-a network that has at least one server to provide
services to the client computers
GLOSSARY EXAM QUESTIONS WITH
COMPLETE ANSWERS
Abstraction - answer-the process of removing or hiding unnecessary detail so that only
the important points remain
Access control - answer-this decides which users have access to which data, and what
they are allowed to do with it
Agent - answer-a computer system that can interpret its environment ( through its
sensors ). It can act autonomously upon that environment ( through its effectors )
Algorithm - answer-a precise method for solving a problem. All instructions given to a
computer must be unambiguous or it won't know what to do.
Analogue - answer-using signals or information represented by a quantity ( e.g. An
electric voltage or current ) that is continuously variable. Changes in the information
being represented are indicated by changes in voltage. This method requires very
accurate sending and receiving systems.
Application programming interface ( api ) - answer-code that allows two programs to
communicate each other
Application software - answer-software that performs a task that would otherwise be
done by hand, perhaps a pen and paper
Arithmetic/logic unit ( alu ) - answer-the part of the cpu that performs calculations and
logic operations
Arithmetic operator - answer-an operator that performs calculation on two numbers
Arithmetic shift - answer-used for signed binary numbers. When performing a right shift,
the bits at the left are replaced by copies of the most significant bit
Array - answer-an organized collection of related values that share a single identifier
Ascending order - answer-this is arranging items from smallest to largest ( e.g. 1,
2 ,3 ,4, 5, 6, 7, or a, b, c, d )
Assembler - answer-translates the mnemonics of assembly language programs into
machine language instructions for the microprocessor to carry out
,Assembly language - answer-a low-level language written using mnemonics
Assignment statement - answer-the set .. To command is used to initialise variables in
pseudocode
Audit trail - answer-a record of activities that have taken place on a computer system.
This record is generated automatically and will record what has happened and who or
what made the change.
Authentication - answer-the process of providing to a computer system who you are
( e.g. Using a username and password )
Autonomous - answer-self-directed and acts without requiring any help or guidance.
Can choose its own goal and uses its experience to achieve it.
Back-up - answer-a copy of files in another location so that they are still available if the
original copy is damaged or lost. Backing up is the process of making a back-up copy.
Bandwidth - answer-the amount of data that can be carried on a network in a given
period of time
Binary - answer-information represented by only two values ( e.g. Voltage or no
voltage ; on or off ). There are no communication errors or misunderstandings because
there are no small differences
Binary digit ( bits ) - answer-the smallest unit of data that is represented in a computer.
It has a single binary value , either 1 or 0.
Binary prefix - answer-multiplies a unit by powers of 2
Binary shift - answer-an operation done on all the bits of a binary value in which they
are moved by a specific number of places to either left or right
Bit depth - answer-the number of bits used to encode the information from each sample.
Increasing the number of bits used increases the amount of detail contained in each
sample.
Block of code - answer-a grouping of two or more code statements
Bluetooth - answer-a protocol for the short-range wireless interconnection of mobile
phones, computers, and other electronic devices
Boolean - answer-something that can take only the values true or false ; named after
english mathematician george boole
, Brute force - answer-an algorithm design that does not include any techniques to
improve performance, but instead relies on computing power to try all possibilities until
the solution to a problem is found
Bug - answer-an error or flaw in a computer program
Built-in functions - answer-functions that are provided in most high-level programming
languages to perform common tasks
Bus - answer-a group of connections between devices in a computer
Bus width - answer-the number of wires that make up a bus. This determines the range
of binary numbers that can be communicated
Byte - answer-the basic combination of bits used to represent an item of information. A
byte typically consists of 8 bits
Cache - answer-a temporary data store so that the data can be accessed very quickly
when needed
Cache memory - answer-memory used to make up for the difference in speed between
two internal components
Cache miss - answer-when the data requested for processing by a component or
application is not found in the cache memory
Carbon footprint - answer-the amount of carbon dioxide an individual or organization
produces as a result of the energy they consume
Central processing unit ( cpu ) - answer-hardware device that carries out the processing
in a computer
Character set - answer-the defined list of characters recognised by a computer's
hardware and software
Checksum - answer-a technique for finding errors. A mathematical formula is applied to
the date and the resulting number value is tansmitted with the date. The recipient
computer applies the same formula to the received data. It then compares the
checksum sent with the date to the calculated checksum. If the checksums don't match,
the data is likely to have been corrupted. So, the recipient computer requests the data
again.
Ciphertext - answer-encrypted plaintext
Client-server network - answer-a network that has at least one server to provide
services to the client computers
