AQA 2024 A-Level Computer Science paper 2

AQA 2024 A-Level Computer Science paper 2 Parallel data transmission - ANS-Multiple bits are sent down several wires simultaneously. Peer-to-peer network - ANS-A network that has no dedicated servers. All computers are of equal status and can both share resources themselves and use resources from other computers, ie they are peers. Pharming - ANS-When a phisher changes DNS server information so that customers are directed to another site. Phishing - ANS-When someone tries to get you to give them your personal information. Plain text - ANS-Message data before it is encrypted. Pointer - ANS-A variable that contains a memory address. The pointer 'points' to the memory location with that address. Pointer type - ANS-A variable of pointer type that stores an address of a data value. Polymorphism - ANS-Giving an action one name that is shared up and down a class hierarchy. Each class in the hierarchy implements the action in a way appropriate to itself. Polynomial time algorithm - ANS-An algorithm whose execution time grows as a polynomial of input size. Precision - ANS-The maximum number of significant digits that can be represented. Absolute Error - ANS-The difference between the actual number and the nearest representable value. Abstract Data Type (ADT) - ANS-A data type whose properties are specified independently of any particular programming language. Abstract data type (ADT) - ANS-A data type whose properties are specified independently of any particular programming language. Abstraction - ANS-Representation that is arrived at by removing unnecessary details. Aggregation - ANS-A type of association where the aggregated object has a weaker form of association with the objects that it is aggregating than is the case with composition. These objects have an existence independent of the aggregated object and can continue to exist even after the aggregated object is disposed of. Ajax - ANS-Web technology that allows only the part of a web page that needs updating to be fetched from the web server. Algorithm - ANS-A sequence of unambiguous instructions for solving a problem. It can be represented as a Turing machine program. Application programming interface (API) - ANS-A layer of software that allows application programs to call on the services of the operating system. Association - ANS-If the relationship is not inheritance or aggregation it is an association. Asymptotic behaviour of f - ANS-Behaviour of the function f(n) for very large values of n. Asynchronous serial data transmission - ANS-Transmission system in which the sender and receiver have separate clocks which are not kept synchronised. Instead, the clocks are synchronised temporarily at the start of a transmission. The arrival of data cannot be predicted by the receiver; s a start bit is used to signal the arrival of data and to synchronise the transmitter and receiver temporarily. Attribute - ANS-A property or characteristic of an entity (databases) or an object (OOP). Automation - ANS-Turning an abstraction into a form that can be processed by a computer. Bandwidth - ANS-For a transmission medium, the range of signal frequencies it may transmit. Base case - ANS-A value that has a solution which does not involve any reference to the general case solution. Baseband system - ANS-A system that uses a single data channel system in which the whole bandwidth of the transmission medium is dedicated to one data channel at a time. Basic operation - ANS-The operation which contributes most to the total running time. Baud rate - ANS-The rate at which signals on a wire may change. Behaviours - ANS-The functions of the object or what the object does. Bit rate - ANS-The number of bits transmitted per second. Broadband - ANS-A multiple data channel system in which the bandwidth of the transmission medium carries several data streams at the same time.