Eduqas A-Level Computer Science Practice Flashcards

Comprehensive vocabulary flashcards covering Eduqas A-Level Computer Science Component 1 and 2, including data structures, logic, systems analysis, architecture, and databases.

Array

A fixed-size, fixed-type collection of elements accessed by an index number; can be one-dimensional (a list), two-dimensional (a grid), or three-dimensional (a cube).

Record

A structure that groups together several related fields, which can be of different data types, under a single named variable.

Stack

A LIFO (Last In, First Out) structure where operations are push (add to top) and pop (remove from top).

Queue

A FIFO (First In, First Out) structure where operations are enqueue (add to rear) and dequeue (remove from front).

Tree

A hierarchical, non-linear structure of nodes connected by edges, starting from a single root node with no cycles.

Linked list

A sequence of nodes where each node stores data plus a pointer to the next node, and sometimes a pointer to the previous node too.

Hash table

A structure that applies a hashing function to a key to calculate directly where to store or retrieve associated data, allowing very fast average-case access.

XOR (exclusive OR)

A logical operation where the output is TRUE if the inputs are different from each other (exactly one is TRUE).

De Morgan's Laws

$\text{NOT}(A \text{ AND } B) = (\text{NOT } A) \text{ OR } (\text{NOT } B)$ and $\text{NOT}(A \text{ OR } B) = (\text{NOT } A) \text{ AND } (\text{NOT } B)$, used to simplify Boolean expressions.

Algorithm

A precise, unambiguous, finite sequence of steps that solves a problem or completes a task.

Scope (of a variable)

The region of a program in which a variable can be accessed, such as local (within a subroutine) or global (accessible from anywhere).

Recursion

When a subroutine calls itself to break a problem into smaller identical sub-problems, requiring a base case to stop the process.

DIV

An operation that performs integer division and discards any remainder, for example $(17 \text{ DIV } 5 = 3)$.

MOD

An operation that returns only the remainder of a division, for example $(17 \text{ MOD } 5 = 2)$.

Validation

An automated check that data entered is sensible, reasonable, or meets defined rules, such as range or type checks.

Verification

A check that data has been copied or transferred accurately, such as double entry or visual checking against a source document.

Bubble sort

An algorithm that repeatedly steps through a list, comparing adjacent elements and swapping them if they are in the wrong order; average time complexity is $O(n^2)$.

Quicksort

A divide-and-conquer algorithm that selects a pivot, partitions the list into smaller and larger elements, and recursively applies the process; average complexity is $O(n \log n)$.

Binary search

A search algorithm for sorted lists that repeatedly compares the target to the middle element and discards the half that cannot contain the target; complexity is $O(\log n)$.

Big O notation

A way of describing how the time or space an algorithm needs grows as the input size ($n$) increases.

Object-oriented programming (OOP)

A paradigm that organizes code around objects created from classes, which define attributes (data) and methods (behaviors).

Backus-Naur Form (BNF)

A formal notation for defining the grammar of a language using production rules, such as $\langle\text{digit}\rangle ::= 0|1|2|...|9$.

Waterfall methodology

A linear, sequential approach to system development where each stage must be fully completed before the next begins.

Agile methodology

An iterative approach that develops software in short cycles called sprints, regularly adapting to changing requirements.

Data Flow Diagram (DFD)

A visual representation of a system's data flow and information processing using symbols for data stores, external entities, processes, and flows.

Alpha testing

Testing carried out in-house by the development team before the software is released to any external users.

Perfective maintenance

Changes made to improve the performance, efficiency, or add enhancements to a system, rather than just fixing bugs.

Compiler

A translation program that converts the entire source program into machine code in one pass, producing a standalone executable file.

Interpreter

A translation program that executes source code line by line at runtime without producing a separate standalone executable.

Lexical analysis

The first stage of compilation which tokenises source code and strips whitespace and comments.

Computer Misuse Act 1990

UK law making it illegal to access computers without permission, access with intent to commit further offences, or make unauthorized modifications to data.

Data Protection Act 2018

The UK implementation of GDPR requiring personal data to be processed lawfully, kept accurate, stored securely, and used only for specified purposes.

Von Neumann architecture

A computer design where a single shared memory stores both instructions and data, leading to a potential bottleneck.

Harvard architecture

A contemporary architecture that uses separate memory and separate buses for instructions and data.

Cache memory

A small, fast memory area between the CPU and RAM that stores frequently or recently used data to reduce access time.

Two's complement

A method for representing signed integers in binary by inverting all bits of the positive value and adding 1.

Serial transmission

The transmission of data one bit at a time, sequentially down a single wire or channel.

Multiplexing

The process of combining multiple separate signals into a single transmission medium efficiently.

First Normal Form (1NF)

A database condition where repeating groups are eliminated and each field holds only a single atomic value.

Second Normal Form (2NF)

A database condition where the table is in 1NF and all partial dependencies are removed, meaning every non-key field depends on the entire primary key.

Third Normal Form (3NF)

A database condition where the table is in 2NF and transitive dependencies are removed, meaning non-key fields depend only on the primary key.

Kernel

The central part of the operating system responsible for managing fundamental resources like memory protection, peripherals, and processes.

Interrupt

A signal generated by hardware or software that temporarily pauses the CPU's current task to deal with an event requiring immediate attention.