MSCE Computer Studies key terms

An electronic device that accepts data as input, processes it under the control of stored instructions, stores the results, and produces output. Computers range from small embedded chips to room-sized supercomputers.

A very powerful computer built from many processors working in parallel. It is used for demanding scientific tasks such as weather forecasting, climate modelling, molecular simulation and code breaking, where huge amounts of calculation must be completed quickly.

A computer built into another device to control its operation. It usually runs one fixed program, may have limited memory and often responds to sensors in real time, for example in washing machines, cars or medical implants.

The main component that executes program instructions. It fetches instructions and data from memory, decodes them, performs the required operations and writes results back. Its speed and number of cores strongly affect overall system performance.

The part of the processor that performs arithmetic and logical operations. It adds, subtracts, compares values and carries out Boolean operations such as AND, OR and NOT, working on data held in registers.

A very small, very fast storage location inside the processor. Registers hold the instruction being executed, addresses, and operands during calculations. They are much faster than cache or main memory but limited in number.

A small, high-speed memory close to the processor that stores frequently used instructions and data. It reduces the time the CPU waits for slower main memory, improving performance; levels are labelled L1, L2 and L3.

Random Access Memory is the main working memory of a computer. It holds programs and data currently in use, can be read and written quickly, and loses its contents when power is switched off, so it is volatile.

Read Only Memory is non-volatile memory whose contents are normally written during manufacture and cannot be changed by ordinary programs. It often stores firmware such as the start-up instructions needed to boot a computer.

System software that manages hardware and provides services for application programs. It controls memory, processors, storage and input/output devices, and offers a user interface, file management and security features.

A small program that helps maintain and manage a computer system. Examples include disk cleanup tools, backup software, antivirus scanners and file compression programs. Utilities usually perform housekeeping tasks rather than user productivity work.

Software that allows the operating system to communicate with a particular hardware device. It translates general commands into the specific signals the device understands, and is often supplied by the device manufacturer.

A way of interacting with a computer using visual elements such as windows, icons, menus and a pointer, usually controlled by a mouse or touch screen. It contrasts with a command-line interface, where users type text instructions.

The smallest unit of data in a computer, representing a single binary digit. A bit has exactly two possible values, 0 or 1. Groups of bits are used to represent numbers, characters, images and instructions.

A group of eight bits treated as a single unit. A byte can represent 256 different values and is commonly used to store one character, or to measure memory and storage capacity in kilobytes, megabytes and gigabytes.

A number system that uses only two digits, 0 and 1, with place values that are powers of two. Computers use binary because electronic circuits can easily represent two states, such as off and on.

A base-16 number system using digits 0 to 9 and letters A to F. Each hexadecimal digit represents exactly four binary bits, so it gives programmers a short, readable way to write long binary values such as memory addresses.

American Standard Code for Information Interchange, a character encoding that maps letters, digits, punctuation and control codes to numbers. Standard ASCII uses seven bits and covers 128 characters; extended versions use eight bits.

A universal character encoding standard that assigns a unique number, called a code point, to characters from almost every writing system. It supports many more characters than ASCII, including accented letters, symbols and non-Latin scripts.

Application software used to create, edit, format and print text documents. It provides features such as spell checking, font formatting, tables, headers and page layout. Typical examples are Microsoft Word and Google Docs.

Application software organised as a grid of rows and columns, used for calculations and data analysis. Cells can hold numbers, text or formulas that recalculate automatically when values change. It is widely used for budgets and financial models.

The address of a cell in a spreadsheet, formed from its column letter and row number, such as B7. Cell references are used in formulas and can be relative, absolute or mixed, controlling how they change when copied.

An organised collection of related data stored so that it can be searched, updated and retrieved efficiently. Computer databases are usually controlled by database management software and may contain many tables linked by keys.

A field or combination of fields that uniquely identifies each record in a database table. No two records may share the same primary key value, and it cannot normally be left empty, ensuring reliable data retrieval.

Two or more computers connected so that they can share data, hardware and services. Connections may be wired or wireless, and networks range in size from a few devices in one room to the global internet.

A network covering a small geographical area such as a home, office or school. Devices on a LAN are usually close together and connected by cables or Wi-Fi, allowing fast data transfer and shared resources like printers.

A set of rules that governs how data is exchanged between devices on a network. Protocols define message formats, timing and error handling, allowing equipment from different manufacturers to communicate. Common examples include TCP/IP, HTTP and Ethernet.

A numerical label assigned to each device on a network that uses the Internet Protocol. It identifies the device and helps route data packets to it. IPv4 addresses are 32-bit; IPv6 addresses are 128-bit.

A network device that forwards data packets between different networks, choosing the best path for each packet. Home routers also connect a local network to an internet service provider and often provide Wi-Fi access.

A finite sequence of clear, unambiguous steps for solving a problem or completing a task. An algorithm must terminate and should produce the correct result for all valid inputs. Algorithms can be represented as pseudocode or flowcharts.

A diagram that represents an algorithm using standard symbols. Ovals show start and end points, parallelograms show input and output, rectangles show processes, and diamonds show decisions, with arrows connecting the steps.

A named storage location in a program whose value can change while the program runs. A variable has a name, a data type and a current value. Assignment statements are used to update it.

A programming construct that repeats a block of instructions until a condition is met or a fixed number of repetitions is reached. Common forms include for loops, while loops and do-while loops.

A program that translates source code written in a high-level language into machine code before the program runs. The resulting executable can run independently of the compiler, but any change to the source requires recompilation.

Malicious software designed to damage, disrupt or gain unauthorised access to a computer system. Types include viruses, worms, trojans, ransomware and spyware. Protection requires up-to-date antivirus software and cautious user behaviour.

Hardware or software that monitors and controls incoming and outgoing network traffic using predetermined security rules. It can block unauthorised connections while allowing legitimate traffic, helping protect a computer or network from attack.

The process of converting readable data, called plaintext, into an unreadable form called ciphertext using a mathematical algorithm and a key. Only someone with the correct key can decrypt it, protecting data during storage or transmission.

A form of social engineering in which attackers send fraudulent messages that pretend to come from a trusted organisation. The messages trick recipients into revealing passwords, bank details or other sensitive information, often through fake websites.

A copy of data stored separately from the original so that it can be restored if the original is lost, damaged or corrupted. Regular backups protect against hardware failure, accidental deletion, malware and disasters.

A legal right that gives the creator of an original work control over how it is copied, distributed and used. Software, text, music and images are protected, and installing or sharing copies without permission may be illegal.