30 of the Computer Science glossary’s terms, each with the part of the syllabus where you first meet it.
A single entity in a program, created from a class, that holds its own values for the class's attributes and can carry out the class's methods.
The machine learning task of finding objects in an image or video, marking each one's position (usually with a bounding box) and classifying what it is.
A programming paradigm in which a program is built from objects, each combining data with the methods that act on that data, and each created from a class that describes its kind.
The set of difficulties that arise when data held as objects in an object-oriented program must be stored in, and rebuilt from, the flat tables of a relational database.
A software library that converts automatically between objects in a program and rows in relational tables, generating the SQL needed to save and load objects.
A specific outcome that a solution must achieve for the problem to count as solved.
A design pattern in which one object, the subject, keeps a list of observer objects that share a common interface, and calls a method on each of them whenever its state changes, so observers can be added or removed without changing the subject.
A group of exactly 8 bits; an IPv4 address is made of four octets.
A multidimensional view of data in which each axis is a dimension, such as time, product or region, and each cell holds numeric measures, such as sales, for one combination of dimension values.
A way of turning a categorical feature into numbers by creating one new binary column per category, set to 1 for the record's category and 0 for all the others.
The interactive analysis of large volumes of historical data from several points of view (dimensions), using complex, read-only queries that summarise data, to support decision-making.
Repeated or severe abusive behaviour directed at a person through digital channels, such as threats, insults, stalking, doxxing (publishing private details) or sharing sexual images without consent.
The processing of large numbers of short, concurrent transactions that insert, update or read a few records each, as in the operational systems that run an organisation's daily activity.
The part of a machine-code instruction that specifies the operation to perform, such as load, add, store or jump.
A collision resolution strategy in which every entry is stored in the table's array itself; when a key's bucket is occupied, other buckets are tried in a fixed sequence until a free one is found.
A control system in which the output is decided by the input and the control algorithm alone, with no measurement of the result fed back to the controller.
The part of a machine-code instruction that gives the data to be used, or the memory address or register where that data is found.
System software that manages a computer's hardware and resources and provides common services to the programs that run on it.
Giving an operator such as +, < or == a meaning for objects of a user-defined class, by defining the method the language calls for that operator.
A device that reads (and sometimes writes) data on optical discs such as CDs, DVDs and Blu-ray discs, using a laser to detect the pattern of tiny pits and flat areas (lands) along a spiral track.
A problem in which the aim is to find the best solution from a set of possible solutions, according to a measurable objective.
A logic gate whose output is 1 when at least one of its inputs is 1.
The clause that sorts the rows of a result set by one or more columns, each in ascending (ASC, the default) or descending (DESC) order.
A seven-layer reference model of network communication (physical, data link, network, transport, session, presentation, application), used mainly to describe and compare networking functions.
A data value that lies an abnormally long way from the other values of the same feature.
Converting characters that have a special meaning in the destination format, such as <, > and " in HTML, into harmless equivalents before untrusted data is inserted into a page, so that the data is displayed as text and never run as code.
The final layer of a neural network, whose neurons produce the network's predictions.
A description of the information a solution produces: what each item is, its format and units, when it is produced and who receives it.
The result of a model learning the noise and specific details of its training data instead of the general pattern, so that it performs well on the training data but poorly on new data.
The error that occurs when the result of a calculation is too large to be represented in the fixed number of bits available.