IB Computer Science SL key terms

A finite, ordered set of unambiguous steps that solves a problem or completes a task, producing a result from given inputs and terminating after a bounded number of operations.

Removing unnecessary detail from a problem or system so that only the features relevant to the task remain, making complex situations easier to model and reason about.

Breaking a large or complex problem into smaller sub-problems that can be solved independently, then combining the solutions to address the original problem.

A structured, language-independent notation using keywords and indentation to describe an algorithm, readable by humans and later translated into a real programming language.

A diagram that represents an algorithm with standard symbols such as rectangles for processes, diamonds for decisions and arrows for control flow between steps.

Repetition of a block of statements controlled by a loop condition, used when the number of repeats is unknown in advance or depends on data.

A technique in which a subprogram calls itself on a smaller version of the same problem, stopping when a base case is reached to avoid infinite calls.

A construct that executes different blocks of code depending on whether a Boolean expression evaluates to true or false, allowing a program to make decisions.

A named storage location in memory whose value can change while a program runs; its identifier, data type and scope determine how it is used.

A classification of values such as integer, real, Boolean, character or string that determines which operations are allowed and how values are stored.

A data type with exactly two possible values, true and false, used in conditions and combined with operators such as AND, OR and NOT.

A collection of elements of the same data type stored under one identifier and accessed by an index, usually numbered from zero or one.

A named, reusable block of code that performs a specific task, may take parameters and may return a value; also called a method, function or procedure.

A named input declared in a subprogram's definition that receives a value when the subprogram is called, allowing the same code to work with different data.

The region of a program in which a particular identifier is visible and can be used, for example a variable declared inside one subprogram only.

A translator that converts a whole high-level language program into machine code before execution, reporting syntax errors and producing an executable file.

A translator that reads and executes a high-level language program one statement at a time, stopping at the first error and requiring the source code to run.

The binary instruction set that a specific processor can execute directly, produced from source code by translation and not normally written by hand.

A search that checks each element of a list in turn until the target is found or the list ends; it works on unsorted data but is slow for large lists.

A search on a sorted list that repeatedly halves the search range by comparing the target with the middle element, giving logarithmic time complexity.

A method that arranges the elements of a collection into a defined order, for example bubble sort, selection sort or merge sort, each with different efficiency.

A last-in-first-out data structure where items are pushed onto and popped from the same end, used for undo operations, recursion and expression evaluation.

A first-in-first-out data structure where items are added at the rear and removed from the front, used for buffering and scheduling tasks.

The encoding of data using only the digits 0 and 1, where each position represents a power of two, used by computers for all stored values.

A single binary digit, either 0 or 1, the smallest unit of data; eight bits form a byte, and bits are grouped to represent larger values.

An organised collection of related data stored so that it can be efficiently queried, updated and shared, usually managed by database management software.

A field or combination of fields whose values uniquely identify each record in a table and that cannot be null or duplicated.

A field in one table whose values match the primary key of another table, creating a link between the tables and enforcing referential integrity.

A declarative language for defining and manipulating relational data, using statements such as SELECT, INSERT, UPDATE and DELETE with clauses like WHERE and ORDER BY.

A set of agreed rules governing how data is formatted, addressed and exchanged between devices on a network, such as TCP/IP or HTTP.

A numeric label assigned to a device on a network so that data can be routed to it, either IPv4 with 32 bits or IPv6 with 128 bits.

A small unit of data sent across a network, containing header information such as source, destination and sequence number, plus a portion of the payload.

The maximum rate at which data can be transferred over a communication channel, usually measured in bits per second and limited by the medium.

The transformation of readable data into an unreadable form using a key so that only authorised parties can reverse it and recover the original content.

The process of verifying that a user or system is who it claims to be, commonly through passwords, tokens or biometric data before access is granted.

System software that manages hardware resources such as memory, processor time and storage, and provides services and an interface for application programs.

A technique in which part of secondary storage is used as an extension of main memory, allowing programs larger than physical RAM to run, at a cost in speed.

A small, fast memory close to the processor that holds recently or frequently used data and instructions to reduce average access time.