Definitions Flashcards
Bit
A single unit of binary (binary digit)
Binary
A numbering system consisting of 1s and 0s
Byte
8 bits in a byte
Binary shift left
Will double the number
Binary shift right
Will divide the number by 2
Pixel
The smallest representable part of an image. Stands picture element.
Colour depth
The amount of bits needed to represent all the colours in an image.
Image Resolution
The amount of pixels in a given area
Analogue sound
A none digital sound wave
Digital sound
A sound as represented by binary numbers.
Sample rate
The amount of sound samples taken from an analogue every second. (Hertz)
Sound resolution
The amount bits required to store all the sounds in an audio file.
Lossy compression
Data is permanently removed from a file when it’s compressed.
Lossless compression
No data is permanently removed from the when it’s compressed.
Run length encoding
A form of lossless compression. Uses frequency of data pairs to shrink file size.
Bit-depth
The amount of bits needed to store a given amount of combinations of binary.
Hardware
The physical parts of a computer
Software
The instructions carried out on a computer
System Software
Software required for a computer to run
Utility Software
A type of system software used to manage a computer system
Operating System
Software that provides a user interface, manages memory, the processor, storage
Application software
Software that carries out a specific task
Peripheral
All devices apart from the processor and primary memory
CPU
The brain of the computer. All inputs and outputs from a computer run through the CPU
Register
High speed memory on the CPU. Stores data needed for the F-D-E cycle (instruction address, data being decided, outputs of calculations)
Cache
High speed memory on the CPU. Stores instructions the processor is likely to reuse.
Von Neumann Architecture
A computer architecture where data and instructions are stored on the same device.
Arithmetic Logic Unit
A component of the CPU which carries out calculations
Control Unit
Coordinates all the activities of a CPU
CPU clock
Controls the timing of the processor – the speed of the clock is measured in hertz. Each pulse represents one CPU cycle
Bus
A set of wires that connect components of a computer
System bus
Includes the Address Bus (transfers memory address), Data Bus (transfers data) & Control Bus (transfers control signals)
Virtual Memory
A partition of secondary storage which is used when RAM is full
BIOS
Basic Input/Output System. Controls and coordinates hardware
Primary Storage
Also known as primary memory, main memory, primary storage. Where instructions are kept for quick access from the CPU. Includes ROM & RAM
Secondary Storage
Where long term instructions are held. For example, installed programs, saved documents and files. Includes magnetic disk, solid state drive & optical disk.
Magnetic storage
A type of secondary storage which uses magnetised disks and a mechanical arm to represent 0s & 1s. (Hard disk drive)
Solid State Storage
A type of secondary storage which uses a current to trap electrons. Trapped electrons can represent 0s & 1s
Optical Storage
Secondary storage that uses pits and lands to represent 0s & 1s and uses a laser to read them
Algorithm
A sequence of instructions carried out to solve a problem
Decomposition
Breaking down a problem into a series of more manageable subproblems.
Abstraction
Removing unnecessary detail from a problem.
Pseudocode
One of the two ways of planning an algorithm. Uses ‘plain English’ text to describe the arrangement of an algorithm
Efficiency of algorithms
The amount of steps required to complete an algorithm (fewer steps = more efficient).
