Cypher’s O Level/IGCSE Computer Science Notes

A set of flashcards based on key concepts from Cypher’s O Level/IGCSE Computer Science notes.

Binary

Base 2 system using only 0s and 1s, where all data must be converted before being utilized by a computer.

Hexadecimal

Base 16 system that is easier to read and takes less space, using digits 0-9 and letters A-F.

Denary

Base 10 system that is easy for humans to read but has less range than hexadecimal.

Overflow Error

Occurs when a number larger than a register can store is generated.

Logical Shifts

Operations that shift bits left or right, losing the most or least significant bits.

Character Set

A tool used to convert text to binary, such as ASCII and Unicode.

Image Resolution

The size or number of pixels in an image.

Color Depth

The number of bits used to represent each color in an image.

Lossy Compression

Reduces file size by permanently removing unnecessary data, often used for images and sounds.

Lossless Compression

Uses algorithms to reduce file size without losing any data, such as RLE.

Packet

A small unit of data that includes a header, payload, and trailer for transmission.

Packet Switching

Method where data is broken into packets that can take separate pathways to their destination.

Serial Transmission

Data sent down a single wire, one bit at a time.

Parallel Transmission

Data sent down multiple wires simultaneously.

Error Detection

Methods like Parity Check and Checksum, which verify data integrity during transmission.

Symmetric Encryption

Uses the same key for both encryption and decryption but is less secure.

Asymmetric Encryption

Uses a public key to encrypt and a private key to decrypt, providing higher security.

Input Device

Hardware used to input data into a computer, such as a keyboard or barcode scanner.

Output Device

Hardware used to output data from a computer, such as printers or speakers.

CPU

Central processing unit responsible for processing instructions and data in a computer.

Secondary Storage

Non-volatile storage that retains data even when power is turned off, such as HDD or SSD.

Static IP Address

An IP address that does not change every time a device connects to a network.

Dynamic IP Address

An IP address that changes every time a device connects to a network.

Phishing

A method of trying to gather personal information using deceptive emails and websites.

Robotics

The design, construction, operation, and use of robots to perform tasks.

AI (Artificial Intelligence)

A branch of computer science that simulates intelligent behavior in computers.

Inference Engine

A component of an expert system that applies rules to a knowledge base to reach conclusions.