MATSEC SEC Computing key terms

A computer design in which one memory holds both instructions and data, and the CPU fetches, decodes and executes instructions one at a time over a shared bus.

The component that carries out program instructions by fetching them from memory, decoding them and performing arithmetic, logic or control operations.

The repeating sequence in which the CPU reads the next instruction from memory, works out what it means, then carries it out before moving on.

A very small, very fast storage location inside the CPU used to hold the current instruction, memory addresses or values being calculated.

A CPU register that holds the address of the next instruction to be fetched, so execution can continue in the correct order or jump elsewhere.

Volatile main memory that holds the programs and data currently in use; its contents are lost when power is removed.

Non-volatile memory whose contents are written at manufacture and normally cannot be changed; it often stores firmware such as the boot program.

A small, fast memory between the CPU and RAM that keeps recently or frequently used data close to the processor to reduce waiting time.

A technique that uses part of secondary storage as an extension of RAM, swapping pages between disk and memory so larger programs can run.

Dividing memory into fixed-size blocks called pages so that programs can be stored in non-contiguous locations and swapped to disk.

Non-volatile storage such as a hard disk, SSD or USB drive that keeps data permanently when the computer is switched off.

Secondary storage built from flash memory chips with no moving parts, giving fast access, low power use and quiet operation.

System software that manages hardware, memory, files and processes, and provides services so application programs can run on the machine.

A signal that tells the CPU to pause its current task, deal with an urgent event such as a key press or disk completion, then resume.

Software stored permanently in hardware, such as the code that starts a device or controls an embedded system, and rarely changed by users.

A small computer built into a device to perform a dedicated control task, such as a washing machine controller or a car engine unit.

A numeric label assigned to a device on a network so data can be routed to and from it, such as 192.168.1.10 in IPv4.

A number used with an IP address to show which part identifies the network and which part identifies the host device.

A unique hardware identifier burned into a network interface card, used for communication within a local network segment.

A distributed service that translates human-readable domain names such as example.com into the numeric IP addresses computers use.

The full address of a resource on the internet, giving the protocol, server name and path, for example https://example.com/page.

The request-response protocol used by web browsers and servers to transfer pages and other resources across the internet.

HTTP carried over an encrypted connection, so data between browser and server is protected against interception and tampering.

A device that forwards data packets between different networks, choosing a path towards the destination using IP addresses.

A network device that connects devices in a local area network and forwards frames only to the port where the destination MAC address is found.

Splitting data into small packets that travel independently across a network and are reassembled at the destination in the correct order.

The core suite of protocols for the internet: IP handles addressing and routing, while TCP ensures reliable, ordered delivery of data.

Scrambling data using a key so that only authorised parties can read it, protecting information during transmission or storage.

Software or hardware that filters incoming and outgoing network traffic against rules, blocking unauthorised access to a system.

A finite, ordered set of unambiguous steps that solves a problem or performs a task, independent of any particular programming language.

A structured, English-like way of writing an algorithm using programming constructs without the strict syntax of a real language.

A diagram that represents an algorithm using standard symbols for processes, decisions and input or output, connected by arrows.

A search that checks each item in a list in turn until the target is found or the list ends; it works on unsorted data.

A search that repeatedly halves a sorted list, comparing the target with the middle item, which is much faster than checking every item.

A sorting algorithm that repeatedly compares adjacent items and swaps them if out of order, moving the largest values to the end.

A way of describing how the running time or memory use of an algorithm grows as the input size increases, such as O(n) or O(log n).

A named storage location in a program whose value can be changed while the program runs, with a type and a scope.

A classification of values, such as integer, real, Boolean or string, that determines what operations can be performed on them.

A named value that is set once and cannot be changed during program execution, making code clearer and safer.

Repeating a block of code a set number of times or until a condition changes, using loops such as for and while.

Choosing which block of code to run by testing a condition, using constructs such as if, else and case statements.

A named block of code that performs a task, may take parameters and may return a value, and can be called repeatedly.

A named value listed in a function or procedure definition that receives an argument when the routine is called.

A technique where a function calls itself on a smaller version of the problem, with a base case to stop the calls.

Converting a value from one data type to another, for example turning a real number into an integer or a string into a number.

An organised collection of related data stored so that it can be searched, updated and shared efficiently by many users.

A database that stores data in tables of rows and columns, linked by keys, and is queried using a language such as SQL.

A column or combination of columns whose value uniquely identifies each row in a table and cannot be duplicated or null.

A column in one table that refers to the primary key of another table, creating a link between the two tables.

The standard language for creating, querying and updating relational databases, using statements such as SELECT, INSERT and UPDATE.

Organising tables to reduce duplicated data and avoid update errors, usually by splitting data into related tables linked by keys.

The field of computing concerned with systems that perform tasks normally needing human intelligence, such as learning or recognising images.

A branch of artificial intelligence in which programs improve at a task by finding patterns in data rather than following fixed rules.

The labelled or example data used to teach a machine learning model so it can make predictions on new, unseen data.

Using remote servers over the internet for storage, processing or software, instead of owning and maintaining local hardware.