Flashcards
GCSE AQA Computer Science - Definitions
Cards in this deck (61)
- 1IdentifierA unique name for something.
- 2ConstantA named value within a program that is assigned a specific value.
- 3VariableAn identifier associated with a particular memory location, used to store data.
- 4Data typeA formal description of the type of data being stored in a variable. It defines the amount of memory required and the type of operations that can be performed on that variable.
- 5IntegerData type for whole numbers.
Typically uses 2 or 4 bytes. - 6BooleanTrue or False
- 7AssignmentWhen a variable is a given a value.
- 8AlgorithmA series of instructions that solves a problem in a finite number of steps and that always ends.
- 9PseudocodeA way of writing an algorithm that is close to actual programming language, using coding-style constructs such as IF...THEN...ELSE, loops and array notation as appropriate.
- 10Logical operatorsNOT, AND, OR. Used in conditions/Boolean expressions.
- 11SequenceWhere instructions are executed one after another in series.
- 12SelectionWhen the program will execute certain instructions based on conditions. Selection statements include: IF... THEN... ELSE and CASE... OF to select which commands to execute.
- 13IterationWhere a program will execute a group of instructions zero or more times based on a condition.
- 14ProcedureA block of code that performs a specific task. It has an identifier by which it can be called from within the program.
- 15FunctionA block of code that always returns a single value.
- 16ParameterA variable whose value is being passed into a function or procedure
- 17Global VariableA variable that is declared in the main program and can be accessed anywhere in the program.
- 18Local VariableA variable that is declared within a function/procedure, so it can only be accessed within that function or procedure.
- 19SyntaxA set of rules that defines how program statements must be written in order for the translator to understand them.
- 20IDEIntegrated Development Environment. A programming environment that provides features such as: code editing, debugging help and run-time diagnostics.
- 21Trace TablesA manual way of tracking progress through an algorithm before it is coded. It tracks the changing values of variables through the code.
- 22DatabaseA file of records.
- 23APIApplication Programming Interface. The interface provided by operating systems for programmers to create their own applications that run on it.
- 24Open Source ProgramsPrograms that are shared free of charge by developers and can be used in other programs, as long as the resulting product is also Open Source.
- 25Data StructuresTemporary structures in main memory that hold multiple data items while a program is running.
- 26ArrayA collection of data items with the same data type, which are grouped together under a single identifier.
- 27Waterfall ModelA series of separate stages; each one is completed and provides inputs to the next.
- 28Cyclical ModelStructured stages as in the Waterfall Model, but once the system is in maintenance stage it generates new problems that lead back into the feasibility and so on.
- 29Spiral ModelHas several iterations of the stages. Successive passes through the stages produce a more refined prototype until the program is complete.
- 30Erroneous DataData that is not the right type such as letters instead of numbers. Should be rejected.
- 31MTBFMean Time Between Failure: A measure of availability often quoted by hardware manufacturers.
- 32CPUCentral processing unit that contains the processor, main memory and cache.
- 33Main Memory/RAMAlso known as Immediate Access Store and Primary Memory.
The memory in the CPU that is used to temporarily store programs while they are running and data used by these programs. - 34ProcessorThe component in the computer that fetches, decodes and executes instructions.
- 35CacheHigh speed memory in the CPU that is used to store a copy of frequently used instructions and data.
- 36Clock SpeedMeasured in Hertz or cycles per second, it represents how many instructions per second the processor can execute.
- 37System BusesThe circuits/internal wiring that connect the components within the CPU together.
- 38RAMRandom Access Memory: a type of memory that is read-write and volatile. Used for Main Memory.
- 39ROMRead Only Memory: memory that is hard-coded at the time of manufacture. Stores the start up programs, the boot-strap loader.
- 40VolatileDescribes memory that loses its contents when the power is switched off.
- 41Non-VolatileDescribes memory that does not lose its contents when the power is switched off.
- 42Virtual MemoryPart of the hard disk that is configured to behave as an extension to main memory.
- 43EEPROMElectronically Erasable Programmable Read Only Memory. A chip made up of a grid of transistors, each of which can be set to the value 1 or 0.
- 44ASCIIAmerican Standard Code for Information Interchange: A 7-bit character set used by PCs.
- 45PixelShort for picture element. It is the smallest component of a bit-mapped image.
- 46MetadataData about data. In the case of image files is the data the computer needs to interpret the image data in the file.
- 47AnalogueA continuously changing wave such as natural sound.
- 48DigitalData that is made up of separate values. How data is stored on a computer.
- 49ADCAnalogue to Digital Converter: Takes real-world analogue data and converts it to a binary representation that can be stored on a computer.
- 50DataFacts and figures with no context or format to give them meaning.
- 51InformationProcessed data that has context and format so that it conveys meaning.
- 52LANA collection of computers and peripherals connected within a single site.
- 53WANA collection of computers and LANs connected together over a geographically remote area, using leased infrastructure.
- 54Peer-to-peerA method of organising devices in a network where devices are all of equal status rather than having specialised roles.
- 55Client-serverA method of organising devices in a network where some computers have specialised roles.
- 56ProtocolA set of rules that defines how devices communicate.
- 57HandshakeThe communication between a client and server that initiates communication.
- 58RecordData stored about one instance of an entity.
- 59FieldOne specific data item being stored such as surname or show size.
- 60QueryA feature of a database system that allows the database to be interrogated. It selects records from the database based on specified criteria.
- 61IndexA mechanism for finding records in a file/database more quickly.
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- This is not a challenge for the light-hearted. You must have complete knowledge of all, to be capable of handing the raw information of this epic unit!
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