Algorithm
A sequence of steps to be performed to solve a problem
Computer Program
An implementation of an algorithm
Data Structure
Specialized format for storing and organizing data
Procedure
A names section of code which performs a task and does not return a value
Function
A named section of code which performs a task and returns a value
Parameter
A special type of variable which can be passed through sub-routines
Scope
The reach of a variable/data structure
Computer System
A combination of software and hardware
Character
Single Value "a" or "9"
Integer
Whole Number
Boolean
True or False Value
ASCII
Character Set: Limited to 7 bits, only applicable in Latin based languages
Real
Integer or Decimal Number
Binary
Composed of 1's and 0's
Hexadecimal
Composed of Integers 0-9 and Strings A-F
Denary
Composed of Digits 0-9
Run-Time Error
Error that occurs while the program is running
Unicode
Alternative character set
Iteration
The process of repeating steps
Selection
A question is asked and from the response several paths can be taken
Sequence
The order in which instructions are performed
Logic Error
An error in the logic of the code which causes it to run incorrectly but not crash
Syntax Error
An error in the syntax of the code Will cause the program to crash
Sample Rate
The frequency at which samples are taken
Requirements
When the team decides what the software needs to do, To think about what the user will want the program to do
Design
Working out the smaller details of the program by breaking it down into smaller chunks
Implementation
The program code is written
Testing
Testing the program under various conditions to make sure it is going to work
Evolution
Maintaining and updating the program
Lossy Compression
Removes some of the file's original data to reduce file size
Resolution
How tightly packed the pixels are
Bit Map Image
Images composed of lots of pixels
Vector Image
Image created in graphics packages and consist of shapes called objects
Lossless Compression
Various algorithms are used to find parts in the data that are repeated
Ring Topology
Fast data transfer but if one machine fails the whole network will fail.
Bus Topology
Easy and cheap to install but if the main cable fails the whole network will crash
Star Topology
Reliable and high-performing but expensive to install and if a hub/switch fails the devices will not have network connection
CPU
Brains of the computer. Mainly processes and uses data to perform taks
GPU
A chip/processor designed to boost the performance of games and graphics
RAM
Primary Storage device which allows data to be stored and retrieved on the machine
Volatile Memory
Memory which only maintains it's storage while the machine is active
Non-Volatile Memory
Memory which maintains it storage whether or not the machine is active
Logic Gate
A diagram which represents boolean logic
Virtual Memory
Memory that appears to be main storage although most if it is held in secondary storage
Cache
Memory that is easily accessed by the CPU and is very fast
Secondary Storage
Non-Volatile memory that is not directly accessible by the CPU
Optical
Data is recorded by making marks in a pattern that can be read back with the aid of light.
Magnetic
A mechanical device in which the media is inserted
Solid State
A grid of electrical cells which quickly send and receive data
NOT gate
A logic gate that takes in 1 input & outputs the opposite
AND gate
A logic gate that takes in 2 inputs and only outputs True if both inputs are True
OR gate
A logic gate that takes in 2 inputs and outputs True if either inputs are True
Truth table
A table which holds possible states on inputs and shows the corresponding final output of a logic diagram
Logic Diagram
A diagram combining multiple logic gates to show the inputs and final output of a system
Boolean Logic
Logic which can only produce a True or False outcome
Hardware
The physical elements of a computer system
Sotware
The logical programmed parts of a computer system that tells the hardware how to function
Embedded system
A system developed for a single, or set purpose. E.g. A washing machine, microwave, digital watch
General Purpose System
A computer system that can change its purpose by adding more software
ROM
Non Volatile. Small area of memory which holds the boot up program.
Device Driver
A program stored on the hard drive that tells the computer how to communicate with a hardware device such as a printer, mouse, or keyboard.
Defragger
System software which tidies up the physical locations of where data is saved on a storage device.
Scheduler
System software which establishes the order in which instructions are executed by the processor
GUI
A User Interface which incorporates the four elements of Windows, Icons, Menus, & Pointers
System Software
software responsible for the general operation of a computer system, including the operation of hardware, running application software, and file management
Application Software
computer software created to allow the user to perform a specific job or task. eg. Word, Excel, browsers, games
Autoupdate
A scheduled patch to software (usually system software) to ensure that it is completely up to date with the latest features.
Firewall
A security system consisting of a combination of hardware and software that limits the exposure of a computer or computer network to attack from crackers
Spyware
A computer program which is installed without permission, sometimes through a virus or sometimes as part of the installation of a program. It works by collecting information and sending it back to another source. The information collected could include the websites you have been visiting or what you have been downloading. This can be used for marketing purposes but also for fraud.
Antivirus
System software that is specifically designed to detect viruses and protect a computer and files from harm
Computer Virus
a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer
Computer Worm
Self-replicating program designed to carry out some unauthorised activity on a victim's computer. This software can spread themselves from one computer to another without any assistance from victims.
Trojan
A piece of software that appears to be a legitimate application, utility, game, or screensaver that performs malicious activities surreptitiously
Phishing
An attack that sends an email or displays a Web announcement that falsely claims to be from a legitimate enterprise in an attempt to trick the user into surrendering private information
Fetch-Decode-Execute Cycle
This is the process that all Stored Program Computers follow in order to run instructions within the machine. Instructions are stored within main memory as a combination of both instruction & data.
Microprocessor
Another name for the central processing unit that is generally made from a single integrated circuit. Multi-core CPUs are made up of more than one microprocessor.
Control Unit
Component of a processor that directs and coordinates most of the operations in the computer.
Arithmetic Logic Unit (ALU)
The circuits that do the math and logic operations inside the processor. The "gateway" all inputs and outputs pass through.
CPU Register
Internal memory in the CPU. These store information that the arithmetic and logic units need to carry out the current instruction.
Program Counter (PC)
A register inside the CPU which holds the address of the next instruction to process.
Current Instruction Register (CIR)
A register inside the CPU which holds the current instruction (not the data)
Memory Address Register (MAR)
A register inside the CPU which holds the address of the current instruction to process. This allows the actual instruction to be loaded.
Memory Data Register (MDR)
A register inside the CPU which holds the data of the current instruction to process.
Accumulator
A register inside the CPU which holds the running total or result of the current instruction.
Address Bus
A physical wire which transmits memory addresses between the CPU and the RAM
Data Bus
A physical wire which transmits data between the CPU and the RAM
Binary Search
Takes the median of a sorted list, and if it is greater than the input, then the top half of the list is removed, and a new list is created until the correct match is found.
Efficiency of algorithms
Speed, Size, Storage
Bubble Sort
Easy to code, however with a longer list can be very inefficient
Name Five Data Types
Integer, Real, Boolean, String, Character
Definite Iteration
Repeating the process until a desired result with a finite number of iterations, that is calculable. Do Until - Loop
Indefinite Iteration
Repeating an iteration that is conditional, and may be repeated infinitely. While-End While
Nested Selection
A selection within a selection
=
Equal to
<>
not equal to
<
less than
greater than
Abstraction
Abstraction is the process of removing all unnecessary information from a set of instructions so that the aim of the instructions is not distracted from and so that the final product is as good as possible. The abstracted data is simpler and more relevant to the operation. Abstraction can speed up the program.
<=
less than or equal to
=
greater than or equal to