Concise Notes for Computer Science Exam

A comprehensive set of flashcards derived from concise notes for preparing for a computer science exam. Each flashcard contains key terms and their definitions, covering a wide range of topics from data representation to software and network protocols.

Benefits of BCD

More straightforward to convert between BCD and denary, less complex to encode and decode, easier for digital equipment to display monetary values exactly.

Applications of BCD

Used in electronic displays like calculators and clocks, storage of date and time in PC BIOS.

Applications of Hexadecimal

Used in MAC addresses, HTML colour codes, memory addresses in assembly language.

ASCII Representation

Each character has a unique code which is stored and replaced in the order of the word.

Character Set

A collection of characters that a computer can represent, with corresponding unique binary numbers.

Differences between ASCII and Unicode

Unicode can represent multiple languages and more characters than ASCII; ASCII is 7-bit while Unicode is 16-bit.

Bitmap Graphic

Composed of pixels, prone to pixelation when enlarged, larger file size, and more difficult to edit.

Vector Graphic

Stores instructions on how to draw shapes, does not pixelate when scaled, has a smaller file size.

Sampling Rate

The number of samples taken per second of sound data.

Lossy Compression

Data is lost and cannot be reconstructed, used when reduced quality is acceptable.

Lossless Compression

Original data is preserved and can be fully restored.

LAN (Local Area Network)

Allows communication and resource sharing between devices in a small geographical area; privately owned.

WAN (Wide Area Network)

Covers a large geographical area and typically has lower data transfer rates.

Client-Server Model

A model where the web server processes requests and returns results to the client.

Peer-to-Peer Network

Each computer is equal in status, allowing data sharing, but has reduced security and management issues.

Cloud Computing

Accessing files/services on a remote server, can be public or private.

Types of Cables

Copper cables transmit data through electrical signals, while fibre-optic cables use light for transmission.

Router

Receives and forwards packets to their destination, maintains a routing table and assigns IP addresses.

DNS (Domain Name System)

Translates domain names into IP addresses for routing on the internet.

Public vs Private IP Address

Public IP addresses are visible on the internet; private IP addresses are used internally within a LAN.

Data Security Measures

Includes strong passwords, firewalls, two-factor authentication, encryption, and regular updates.

Data Integrity

Ensures the accuracy and consistency of data, typically through validation and verification methods.

Normalisation

Process of organizing data to minimize redundancy in a relational database.

Primary Key

A unique identifier for a record in a database table.

Foreign Key

A field in one table that links to the primary key in another table.

Operating System Functions

Manages memory, file systems, security, processes, and hardware interfaces.

Utility Software

Helps maintain computer performance, such as disk formatting, defragmentation, and virus checking.

Compiler

Translates high-level programming code into machine code, creating an executable file.

Interpreter

Translates high-level programming code line by line, executing it immediately.

Ethics in Computing

Involves making decisions that respect user privacy, data security, and professional integrity.