The purpose of a CPU is to process data Custom written software is created for a user to meet exact purpose Off the shelf software is developed by a software company to be sold to the public Open source software is written by public for everyone to use Proprietary software is written by developers to be used by everyone but they cannot access source code An antivirus program detects and protects the computer from virus threats Spyware protection detects and removes spyware (small programs which quietly monitor what you are doing) Firewall restricts communications in and out from the computer from the application which are running Entity is a real world object

Syntax error is grammar in the language A logic error is a problem in a program that causes it to produce unexpected results Array is data structure of several variables under one name A variable represents a value in the program A constant is a label referring to a location in memory containing a value that can be accessed but cannot be changed by the program Integer is a whole number positive or negative (e.g. quantities) Real is a number that can have decimals (e.g. prices) Boolean is a value that can be true or false Character is a single alphabetic or numeric character String is a group of alphabetic and numeric characters

Translator is a program that converts high level code or assembly level Compiler is a translation software which converts high level source code into machine code Interpreter is a translation software that converts source code into machine code which is immediately executed one instruction at a time Machine code is instructions in binary used by the CPU (bit patterns)

Sequence is putting and executing instructions in order Iteration is repetitionSelection is decision Instructions are stored as bit patterns Computers use binary so that they can be based on logic circuits

Peer to peer network means all computers have equal status Virtual memory is a section in the hard disk to store items in RAM which are not being currently used Virtual memory is needed to allow more programs to be loaded when ram is full Secondary storage is used to back up important files or files that are too big to be on main storage

The more bits means the more it matches to the original

Lossy compressions involves removing some of the data from a file in order to reduce size Lossless compression does not remove any data and the file stays the same Compression is reduction in a file size to reduce download times and storage requirements HTML is a text based system for defining web pages

LAN is local area network- confined in one location WAN is wide area network-covers large geographical areas Protocol is a set of rules or standards that control communications between devices DNS meaning domain name system translates domain names into IP addresses Domain name is readable to humans. It is changed to numerical IP address by a DNS server

A database is a persistent organised store of data that can be easily and quickly searched for DBMS = Database Management System Many large databases use DBMS. This system separates the data stored from data handling applications used to maintain and interrogate the database A flat file database is when all the data and fields are stored in one table A relational database is when that data is separated into individual tables (entities) that are linked by a primary key which appears on each table

Tables represent the entities in the database Forms provide customisable user interface to add/edit and delete data Queries allow data that meets specific criteria to be extracted and displayed Reports display reports of queries in a customised format designed to be printed

A range check is commonly used when you are working with data which consists of numbers, currency or dates/times. A type check will ensure that the correct type of data is entered into that field. Check digit is used when you want to be sure that a range of numbers has been entered correctly. A length check can also be set up to allow characters to be entered within a certain range.