Praxis Computer Science key terms

The central processing unit is the main processor in a computer. It fetches instructions, decodes them, and carries out arithmetic, logic, and control operations while coordinating other components.

Temporary, volatile computer memory that holds programs and data currently in use. Its contents disappear when power is lost, but it allows fast reading and writing.

A small, fast memory area close to the processor that stores frequently used instructions and data. It reduces average access time by keeping likely-needed information nearby.

System software that manages hardware resources, provides services to applications, and controls basic operations such as process scheduling, memory allocation, file storage, and device input and output.

A computer design in which instructions and data share the same memory and travel over common pathways. The processor fetches instructions sequentially from memory during execution.

A basic electronic circuit that performs a Boolean operation on one or more binary inputs and produces a binary output. Common examples include AND, OR, and NOT gates.

The repeating sequence a processor follows to execute an instruction, typically fetching it from memory, decoding its operation, executing it, and storing any result.

A finite, ordered set of unambiguous steps for solving a problem or completing a task. A correct algorithm produces the intended result for valid inputs.

A readable, informal description of an algorithm that uses programming-like structures without strict syntax. It helps people plan, explain, and compare solutions before coding.

A named storage location in a program whose value can change during execution. It has an identifier, a data type in many languages, and a current value.

A classification that specifies what kind of values a variable or expression can hold and which operations are allowed, such as integer, floating-point number, character, string, or Boolean.

A programming construct that determines the order in which statements execute. Common forms are sequence, selection, and iteration, enabling branches and repeated actions.

A technique in which a function calls itself to solve smaller instances of the same problem. It requires a base case that stops further calls.

A program that translates source code written in a high-level language into machine code or another target language before the program runs. It usually reports syntax errors during translation.

A program that reads source code and executes it directly, translating and running statements one at a time rather than producing a separate executable file in advance.

A mathematical notation describing how an algorithm's running time or memory use grows as input size increases. It focuses on the dominant growth trend and ignores constant factors.

A database that stores data in tables made of rows and columns and uses relationships between tables. It is queried with languages such as SQL and follows the relational model.

A column or set of columns whose values uniquely identify each row in a database table. It cannot contain duplicate or null values.

A column or set of columns in one table that refers to the primary key of another table. It enforces referential integrity between related records.

Structured Query Language, a standard language for defining, querying, updating, and managing data in relational databases. It includes statements for creating tables and retrieving rows.

The process of organizing relational database tables to reduce duplicated data and avoid update anomalies. It typically involves dividing data into related tables and defining keys.

A data structure that speeds up searches on a database table by providing quick lookup paths to rows. It uses extra storage and must be updated when data changes.

Data that describes other data, such as a file's author, creation date, format, or size. In databases, it describes table structures, constraints, and other schema information.

A numeric identifier assigned to a device on a network so data can be routed to it. IPv4 addresses are 32-bit; IPv6 addresses are 128-bit.

The Domain Name System, a distributed naming service that translates human-readable domain names into IP addresses so browsers and other clients can reach servers.

Hypertext Transfer Protocol, an application-layer protocol used by web clients and servers to request and deliver resources such as web pages, images, and data.

A networking method that divides data into small packets, sends them independently through shared routes, and reassembles them at the destination. It enables efficient, resilient internet communication.

A network device that forwards packets between different networks by examining destination IP addresses and choosing paths based on routing information.

A set of agreed rules and conventions that governs how devices exchange data, including message formats, timing, error handling, and addressing.

The maximum rate at which data can be transmitted over a network connection, usually measured in bits per second. Higher bandwidth can support more data traffic.

The process of converting readable data into an encoded form that unauthorized people cannot easily understand. A key is used to encrypt and typically to decrypt the data.

The process of verifying a user's or system's claimed identity, often through passwords, tokens, biometrics, or multi-factor methods. It answers whether the identity is genuine.

A social-engineering attack that tricks people into revealing sensitive information or clicking malicious links by impersonating a trustworthy organization or person.

Software designed to harm, disrupt, or gain unauthorized access to a computer system. Examples include viruses, worms, ransomware, spyware, and trojan horses.

The gap between people who have effective access to digital technologies and those who do not, often due to cost, location, skills, or infrastructure.

Legal rights that protect creations of the mind, such as inventions, artistic works, software, and trademarks. These rights control use, copying, and distribution.