MATSEC AM Information Technology key terms

A finite, ordered set of unambiguous steps that solves a problem or completes a task. It must terminate and produce a result for every valid input.

Hiding unnecessary detail behind a simpler model so a problem can be handled at a manageable level, such as treating a car as pedals and a steering wheel.

A structured, English-like notation for expressing an algorithm without the strict syntax of a programming language, used to plan logic before coding.

A diagram using standard symbols such as ovals for start and end, parallelograms for input and output, and diamonds for decisions to represent program logic visually.

A named storage location in memory whose value can change while a program runs. Its name refers to the value held at that moment.

A named value that is set once and cannot be changed during program execution, used for fixed quantities such as tax rates or maximum array size.

A classification of values that determines what can be stored and which operations are allowed, for example integer, real, Boolean, character and string.

A data type with exactly two possible values, true and false, used for conditions and for storing the result of comparisons.

A control structure that chooses between alternative paths, implemented with if, if-else or case statements, based on whether a condition evaluates to true or false.

A control structure that repeats a block of statements, either a fixed number of times with a count-controlled loop or until a condition changes with a condition-controlled loop.

A technique where a subroutine calls itself on a smaller version of the same problem, requiring a base case to stop the chain of calls.

A named block of code that performs one task and can be called repeatedly, receiving parameters and optionally returning a value, improving reuse and readability.

A named input declared by a subroutine that receives a value when the subroutine is called, allowing the same code to work with different data.

A fixed-size collection of elements of the same data type, stored together and accessed by an index, usually starting at zero.

A search that checks each element of a list in turn until the target is found or the list ends, working on unsorted data but slow on large lists.

A search that repeatedly halves a sorted list by comparing the target with the middle element, far faster than linear search but requiring sorted data.

A sorting algorithm that repeatedly compares adjacent pairs and swaps them when out of order, so large values gradually move to the end of the list.

A translator that converts an entire high-level source program into machine code before it runs, reporting syntax errors together and producing an executable file.

A translator that reads and executes a high-level program one statement at a time, stopping at the first error and running more slowly than compiled code.

A translator that converts assembly language, which uses mnemonics such as LDA and ADD, into machine code of binary instructions.

System software that manages hardware, memory, files and processes, provides a user interface, and lets application programs run on the computer.

Programs that maintain and protect a computer system, for example antivirus tools, disk defragmenters, backup programs and file compression tools.

A technique where part of secondary storage is used as an extension of RAM, allowing programs larger than physical memory to run, at the cost of slower access.

Dividing memory into fixed-size blocks called pages and frames so that program pages can be loaded into non-contiguous physical memory locations.

Small, very fast memory close to the processor that holds recently or frequently used instructions and data to reduce average access time to main memory.

The central processing unit that fetches, decodes and executes instructions; it contains the control unit, the arithmetic logic unit and registers.

A very small, extremely fast storage location inside the CPU, such as the program counter, accumulator and instruction register, holding data during processing.

The repeating process in which the CPU fetches an instruction from memory, decodes its operation, executes it, and then stores any result.

An organised collection of related data stored so that it can be queried, updated and shared efficiently, usually managed by a database management system.

A field, or combination of fields, that uniquely identifies each record in a table and therefore cannot contain duplicate or null values.

A field in one table that holds the primary key value of a record in another table, creating a link between the two tables and enforcing referential integrity.

Organising tables to reduce duplicated data and update anomalies, typically by moving repeating groups into separate related tables up to third normal form.

Structured Query Language, used to define and manipulate relational data with statements such as SELECT, INSERT, UPDATE, DELETE and CREATE TABLE.

A set of agreed rules governing how data is formatted, addressed, transmitted and acknowledged between devices on a network.

The core suite of internet protocols: IP addresses and routes packets between networks, while TCP establishes connections and guarantees ordered, reliable delivery.

A method of sending data by splitting it into packets that are routed independently across a network and reassembled in order at the destination.

A local area network covering a small geographic area such as a school or office, usually owned by one organisation and offering high data rates.

A wide area network spanning large distances, often connecting several LANs through links owned by telecommunications providers, as the internet does.

A device that forwards packets between networks by reading destination IP addresses and choosing the best path using a routing table.

Scrambling data with a key so that only authorised parties can read it, protecting confidentiality during transmission and storage.

Encryption where the same secret key is used to encrypt and decrypt data, fast and suitable for bulk data but requiring secure key distribution.

Encryption using a public key to encrypt and a mathematically related private key to decrypt, solving key distribution and enabling digital signatures.

A value created by encrypting a hash of a message with the sender's private key, proving the sender's identity and that the message was not altered.

Applying a one-way function that turns data of any length into a fixed-length value, used to verify integrity and to store passwords safely.

A social engineering attack that tricks users into revealing credentials or personal data through fake emails, messages or websites impersonating trusted organisations.

Software written to cause harm or gain unauthorised access, including viruses, worms, trojans, ransomware and spyware.

Hardware or software that inspects network traffic and blocks or allows packets according to rules, protecting a network from unauthorised access.

The stages of building an information system: investigation, analysis, design, implementation, testing, installation and maintenance, each producing documented outputs.

An early assessment of whether a proposed system is technically, economically, legally and operationally viable before major development effort is committed.

A linear development approach in which each phase is completed and signed off before the next begins, giving clear milestones but poor tolerance of late changes.

Building a working, often simplified, version of a system to clarify requirements with users and refine the design before full development.

A copy of data stored separately from the original so that it can be restored after loss, corruption or disaster, ideally following a regular schedule.

The accuracy, consistency and completeness of stored data, maintained through validation, access controls and reliable backup procedures.

Checking that input data is reasonable and within acceptable limits, for example range, length, type and presence checks, before it is accepted by a system.

Checking that data has been copied or transferred accurately, for example by double entry or visual comparison of source and stored values.