Cameroon GCE O-Level Computer Science flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

CPU

Central Processing Unit: the component that fetches, decodes, and executes instructions. It contains the control unit, arithmetic logic unit, and registers.

RAM

Random Access Memory: volatile main memory that temporarily holds programs and data currently in use. Contents are lost when power is switched off.

Cache memory

Small, fast memory between CPU and RAM that stores frequently used instructions and data to reduce average access time.

Fetch-decode-execute cycle

The process where the CPU fetches an instruction from memory, decodes it to determine the operation, and executes it, then repeats.

Hexadecimal

Base-16 number system using digits 0–9 and A–F. Each hex digit represents four binary bits, making it a compact way to write binary.

Two's complement

Method for representing signed integers in binary. The leftmost bit indicates sign; to negate a number, invert all bits and add 1.

ASCII

American Standard Code for Information Interchange: a 7-bit character code representing 128 characters including letters, digits, and control codes.

XOR gate

Logic gate whose output is 1 only when its inputs are different. For two inputs, output = A·NOT B + NOT A·B.

Operating system

System software that manages hardware and software resources, provides a user interface, and runs application programs.

Compiler

Translator that converts an entire source program into object code before execution. It reports errors after compiling the whole program.

Utility program

System software that performs maintenance tasks such as antivirus scanning, backup, disk defragmentation, or file compression.

Flowchart decision symbol

A diamond-shaped symbol in a flowchart that represents a condition with two or more exits, such as yes/no or true/false.

Pseudocode

Structured English-like notation used to describe an algorithm independently of any programming language, using keywords like IF, THEN, WHILE.

Dry run

Manual execution of an algorithm using a trace table to record variable values step by step, used to check logic and find errors.

Binary search

Search algorithm that repeatedly divides a sorted list in half, comparing the middle item, until the target is found or the list is exhausted.

Variable

A named memory location whose stored value can change during program execution. It has a data type and an identifier.

FOR loop

Definite iteration structure that repeats a block a known number of times, using a counter variable with start and end values.

Procedure

A subprogram that performs a task but does not return a value. It may take parameters and can be called from other parts of a program.

Pass by reference

Parameter passing method where the subprogram receives the address of the argument, so changes to the parameter affect the original variable.

Primary key

A field or combination of fields that uniquely identifies each record in a database table. It cannot be null or duplicated.

Foreign key

A field in one table that refers to the primary key in another table, used to create relationships and enforce referential integrity.

SQL SELECT

Statement used to retrieve data from a database table. Syntax: SELECT fields FROM table WHERE condition; it can include ORDER BY and GROUP BY.

Star topology

Network layout where each device connects to a central hub or switch. Failure of one cable does not affect others, but the central device is a single point of failure.

IP address

A unique numerical address assigned to a device on a network. IPv4 uses 32 bits; IPv6 uses 128 bits.

Router

Network device that forwards data packets between different networks using IP addresses, determining the best path for each packet.

Firewall

Hardware or software that monitors and filters incoming and outgoing network traffic according to security rules, blocking unauthorised access.

Ergonomics

Design of equipment and workspace to fit the user, reducing health risks such as repetitive strain injury, eye strain, and back pain.

Digital divide

The gap between those who have access to and skills in information and communication technology and those who do not.

Cloud computing

Provision of computing services such as storage, processing, and software over the internet, typically on a pay-as-you-go basis.

SDLC

Systems Development Life Cycle: the stages of analysis, design, development, testing, implementation, and maintenance used to build an information system.

Parallel changeover

Implementation method where old and new systems run simultaneously for a period, allowing results to be compared and reducing risk.

User documentation

Material such as user manuals, tutorials, and online help that explains how to use a system to end users.