RBSE SS Computer Science key terms

The smallest unit of data in computing, holding a single binary value of either 0 or 1. Groups of bits form bytes and larger units used to measure memory and storage.

A group of eight bits treated as one unit. It commonly stores one character and is the base unit for measuring memory, file size, and storage capacity.

A base-2 positional number system using only the digits 0 and 1. Each position represents a power of two, and it is the native representation used by digital circuits.

A base-16 number system using digits 0-9 and letters A-F. It offers a compact, human-friendly shorthand for binary values, so programmers use it for memory addresses, colour codes, and byte values.

A method of representing signed integers in binary where the leftmost bit indicates sign. Negative values are formed by inverting bits and adding one, allowing subtraction with ordinary addition circuits.

A rule set mapping characters to numeric codes so computers can store and exchange text. Examples include ASCII for basic English characters and Unicode for scripts used worldwide.

A universal character encoding standard assigning a unique code point to characters of most writing systems. It supports multilingual text and is commonly implemented through encodings such as UTF-8.

An error occurring when a computed value exceeds the range that a fixed number of bits can represent. The result wraps around or becomes incorrect, so programmers must choose suitable data types.

System software that manages hardware, memory, files, and processes, and provides services to application programs. It acts as an intermediary between the user and the machine's components.

A translator that converts an entire high-level source program into machine code before execution. It reports syntax errors for the whole program and produces a separate executable file.

A translator that reads a source program line by line, converting and executing each statement in turn. It stops at the first error and does not create a standalone executable file.

A finite, ordered set of unambiguous steps that solves a problem or performs a task. A good algorithm terminates, produces correct output, and uses resources efficiently.

A diagram using standard symbols such as ovals, rectangles, diamonds, and arrows to show the sequence of steps in an algorithm or process. It helps visualise program logic before coding.

A structured, English-like description of an algorithm that follows programming conventions without strict syntax rules. It lets programmers plan logic that can later be translated into any language.

A mistake in the grammar of a program, such as a missing colon or unbalanced bracket, which prevents the code from being translated or run. The interpreter or compiler reports its location.

The human-readable program text written by a programmer in a high-level language. It must be translated by a compiler or interpreter before the computer can execute it.

A high-level, interpreted, general-purpose programming language known for readable indentation-based syntax and a large standard library. It supports procedural, object-oriented, and functional programming styles.

A classification specifying what kind of values a variable can hold and which operations apply to them. Python's built-in types include int, float, str, bool, list, tuple, and dict.

A named reference that stores a value in memory so a program can retrieve or change it. In Python a variable is created by assignment and its type follows the assigned object.

Describing an object whose value cannot be changed after creation. In Python, strings, tuples, and numbers are immutable, so operations on them produce new objects instead of modifying the original.

Leading whitespace at the start of a line that Python uses to define code blocks instead of braces. Consistent indentation is mandatory and incorrect indentation raises an error.

A runtime event signalling that an operation could not complete normally, such as dividing by zero. Python raises exceptions that can be caught with try and except blocks.

A control structure that repeats a block of statements while a condition holds or over a sequence of items. Python provides for loops for iteration and while loops for condition-based repetition.

An ordered, mutable Python collection written in square brackets that can hold items of mixed types. Elements are accessed by index and can be added, removed, or replaced in place.

An ordered, immutable Python sequence written in parentheses. Because it cannot be changed after creation, it suits fixed groups of values and may be used as a dictionary key.

A mutable Python collection storing key-value pairs, where each key is unique and maps to a value. Lookups by key are fast and keys must be immutable objects.

An integer position identifying an element within a sequence. Python indexes start at zero, and negative indexes count backwards from the end of the sequence.

A named, reusable block of code that performs a task and may accept parameters and return a value. Functions reduce repetition and make programs easier to test and maintain.

A variable listed in a function definition that receives a value when the function is called. Arguments are the actual values supplied by the caller for those parameters.

A technique where a function calls itself on a smaller version of the same problem until reaching a base case. It needs a terminating condition to avoid infinite calls.

A linear data structure following last-in, first-out order, where insertion and removal happen at one end called the top. It is used for function calls, undo operations, and expression evaluation.

A linear data structure following first-in, first-out order, where items are added at the rear and removed from the front. It models waiting lines and scheduling tasks.

A linear structure of nodes, each holding data and a reference to the next node. Unlike arrays, it grows dynamically and inserts or deletes efficiently, but cannot be indexed directly.

A collection of elements of the same type stored in contiguous memory and accessed by numeric index. It allows fast direct access but has a fixed size in many languages.

A measure of how an algorithm's running time grows with input size, usually expressed in big-O notation. It helps compare algorithms independently of hardware and implementation details.

A search algorithm that repeatedly halves a sorted collection by comparing the target with the middle element. It runs in logarithmic time but requires the data to be sorted first.

A column or set of columns that uniquely identifies each row in a table. It must be unique and cannot contain null values, and it enforces entity integrity.

A column or set of columns in one table that references the primary key of another table, creating a relationship. It enforces referential integrity by restricting values to existing referenced rows.

A database rule ensuring that every foreign key value matches an existing primary key value or is null. It prevents orphan records and keeps relationships between tables consistent.

The process of organising tables to reduce redundancy and avoid update, insert, and delete anomalies. It proceeds through normal forms such as 1NF, 2NF, and 3NF based on dependencies.

Structured Query Language, the standard language for defining, manipulating, and querying relational databases. It includes statements such as SELECT, INSERT, UPDATE, DELETE, and CREATE TABLE.

An SQL operation combining rows from two or more tables based on a related column. Inner joins return matching rows, while outer joins also keep unmatched rows from one or both tables.

A unique numeric label assigned to a device on a network so data can be routed to it. IPv4 uses 32-bit addresses written in dotted decimal; IPv6 uses 128 bits.

A 32-bit value that separates the network portion of an IPv4 address from the host portion. It tells a device whether a destination lies on the local network or must be sent to a router.

The Domain Name System translates human-readable domain names into IP addresses. It works as a distributed hierarchy of name servers queried before connections are made.

The Hypertext Transfer Protocol defines how web browsers and servers request and deliver resources. HTTPS adds TLS encryption to protect data in transit.

A network device that forwards packets between different networks by choosing paths based on IP addresses. It connects a local network to the internet and links separate subnets.

The process of transforming readable data into ciphertext using a key so that only authorised parties can recover it. It protects confidentiality during storage and transmission.

A social engineering attack that tricks users into revealing credentials or installing malware, often through fake emails or websites. Awareness and verifying senders are key defences.

Any software designed to harm, disrupt, or gain unauthorised access to a system, including viruses, worms, trojans, and ransomware. Antivirus tools and safe browsing habits reduce risk.

A security control that monitors and filters network traffic against defined rules, blocking unauthorised connections. It may be hardware, software, or both, and forms a perimeter defence.

The field of building systems that perform tasks associated with human intelligence, such as learning, reasoning, and language understanding. Machine learning is a major subfield.

The delivery of computing resources such as storage, servers, and software over the internet on demand. Users pay for what they consume instead of owning physical infrastructure.

The process of locating and fixing errors in a program. It uses techniques such as reading error messages, inserting print statements, and stepping through code in a debugger.

A specific set of inputs and expected outputs used to check whether a program behaves correctly. Good test cases include normal, boundary, and invalid inputs.