DSST Computing and IT key terms

A computer design in which a single processor fetches instructions and data from the same shared memory, executing one step at a time. Most general-purpose computers still follow this model.

The central processing unit is the chip that fetches, decodes, and executes program instructions. Its speed is measured in clock cycles per second, and it coordinates the other hardware components.

Random access memory is fast, volatile working storage that holds programs and data currently in use. Its contents disappear when power is removed, so work must be saved to persistent storage.

A storage device that keeps data in flash memory chips with no moving parts. It offers faster access and greater shock resistance than a spinning hard disk but has a finite number of write cycles.

Any hardware device connected to a computer to add input, output, or storage capability, such as a keyboard, printer, or external drive. Peripherals connect through ports or wireless interfaces.

Software that lets the operating system communicate with a specific piece of hardware by translating general commands into signals that device understands. Outdated drivers are a common cause of hardware faults.

The core software that manages hardware resources, schedules programs, enforces file permissions, and provides services to applications. Examples include Windows, macOS, Linux, and Android.

Software distributed under a license that keeps the source code secret and restricts copying, modification, and redistribution. Users buy a right to use it under stated conditions rather than owning it.

Software whose source code is published under a license allowing anyone to inspect, modify, and redistribute it, often with conditions about attribution or sharing derivatives. Examples include Linux and Firefox.

The contract a user accepts before installing software, setting out permitted uses, number of installations, restrictions on reverse engineering, and warranty limits. Its terms are legally binding once accepted.

A volume licensing arrangement that lets an organization install software on a specified number of machines or for a defined group of users at a negotiated price. It is common in schools and businesses.

A legal agreement granting permission to use software under defined conditions, such as seat count, term length, or permitted devices. Using software outside those terms is copyright infringement.

The structured sequence of phases used to build software: planning, requirements analysis, design, implementation, testing, deployment, and maintenance. Different models arrange these phases in different ways.

A sequential development approach in which each phase must be completed and approved before the next begins. It suits stable requirements but makes late changes expensive.

An iterative approach that delivers software in short increments, welcomes changing requirements, and relies on close collaboration with customers. Work is typically organized in repeating sprints with frequent reviews.

Building a simplified working model of a system to clarify requirements and gather user feedback before full development. Prototypes may be discarded or evolved into the final product.

A system that records changes to files over time so developers can review history, revert mistakes, and merge work from multiple contributors. Git is the most widely used example.

A single application bundling a code editor, compiler or interpreter, debugger, and build tools. It streamlines writing, testing, and running programs by keeping these tools in one place.

A program that translates source code written in a high-level language into machine code or another target language before the program runs. Errors are reported during this translation step.

A finite, ordered set of unambiguous steps for solving a problem or completing a task. Algorithms can be expressed in pseudocode, flowcharts, or any programming language.

A structured, informal notation that describes an algorithm using plain-language statements and programming-like constructs. It is not executable but helps designers plan logic before coding.

A diagram that represents the steps of a process or algorithm using standard symbols such as ovals for start and end, rectangles for actions, and diamonds for decisions.

Software that stores, retrieves, and secures structured data, handling queries, concurrency, backup, and access control. Examples include MySQL, PostgreSQL, and Microsoft SQL Server.

A collection of data organized into tables of rows and columns, linked by shared key values. Relationships between tables are expressed through keys rather than physical pointers.

A column or combination of columns whose value uniquely identifies each row in a table. No two rows may share a primary key value, and it cannot be null.

A column in one table that holds a value matching the primary key of another table, creating a link between them. It enforces referential integrity between related records.

A copy of data kept separately so it can be restored after loss, corruption, or attack. Effective backup plans store copies offsite or offline and test restoration regularly.

The process of scrambling data with a mathematical key so that only parties holding the correct key can read it. It protects information in transit and at rest.

Hardware or software that inspects network traffic and blocks or allows it according to configured rules. It forms a barrier between a trusted internal network and untrusted outside networks.

Any software designed to harm, disrupt, or gain unauthorized access to a system, including viruses, worms, ransomware, and spyware. It often arrives through email attachments or malicious downloads.

A deceptive message that impersonates a trusted party to trick recipients into revealing passwords or clicking malicious links. Clues include urgent language, mismatched sender addresses, and unexpected requests.

Software installed without clear consent that secretly collects information about a user's activity, such as browsing habits or keystrokes. It is often bundled with free downloads and can degrade performance.

An electronic document issued by a trusted authority that binds a public key to an identity. Browsers use it to verify that a website is genuine before encrypted communication begins.

A legal right giving creators exclusive control over copying, distributing, and adapting original works such as text, music, software, and images for a limited term. It arises automatically on creation.

A legal doctrine permitting limited use of copyrighted material without permission for purposes such as criticism, teaching, or news reporting. Courts weigh purpose, amount used, and market effect.

The status of works whose copyright has expired, been waived, or never applied, so anyone may use them freely. Government publications and very old texts are common examples.

Presenting someone else's words, ideas, code, or images as one's own without proper attribution. It is an ethical and academic offense and may also breach copyright.

A word, logo, slogan, or symbol registered to identify the source of goods or services and distinguish them from competitors. Trademark law protects against confusingly similar use.

An exclusive right granted for a limited period to an inventor for a new, useful, and non-obvious invention. It lets the holder prevent others from making or selling the invention without permission.

The accepted conventions of polite and considerate behavior in online communication, such as avoiding all-caps shouting, quoting only relevant text, and respecting others' privacy. Breaches can damage reputations and relationships.

Unsolicited bulk electronic messages sent to many recipients, usually for advertising or fraud. Filters and anti-spam laws aim to reduce its volume and impact.

The maximum rate at which data can be transmitted over a connection, usually measured in bits per second. Higher bandwidth allows more simultaneous traffic but does not by itself reduce latency.

The delay between sending a signal and receiving a response, measured in milliseconds. High latency makes video calls and online games feel sluggish even when bandwidth is plentiful.

An agreed set of rules governing how devices exchange data, covering message format, timing, and error handling. Common examples include TCP/IP for internet traffic and HTTP for web pages.

A numeric label assigned to a device on a network so data can be routed to it. IPv4 addresses are 32-bit; IPv6 uses 128 bits to provide far more unique addresses.

The field of building computer systems that perform tasks associated with human intelligence, such as recognizing images, understanding language, and making decisions. Systems learn patterns from data rather than following only explicit rules.

A branch of artificial intelligence in which programs improve at a task by finding patterns in example data instead of being explicitly programmed for every case. Models are trained, then used to predict.

The examples used to teach a machine-learning model to recognize patterns. Biased, incomplete, or unrepresentative data produces unreliable and potentially unfair results.

Systematic unfairness in automated decisions that arises from biased data, flawed design, or unrepresentative testing. It can disadvantage groups in hiring, lending, or policing.

The growing interconnection of economies, cultures, and communication across national borders, accelerated by the internet and low-cost transport. It spreads technology and work but raises concerns about jobs and local culture.

The gap between people who have reliable access to computers, fast internet, and the skills to use them and those who do not. It affects education, employment, and access to public services.

Contracting work to an outside organization, often in another country, rather than performing it in-house. It can lower costs but introduces coordination, language, and time-zone challenges.

The principle that internet service providers should treat all traffic equally, without blocking, slowing, or charging differently for specific sites or content. Rules vary by country and change over time.