Information Representation and Multimedia

Unit 1: Information Representation and Multimedia

Data Representation

• Binary is a base-2 system using 0 and 1.
• A bit is the smallest unit of data in computing.
• One's complement is a way to represent negative numbers by inverting all bits.
• Two's complement is calculated by adding 1 to the one's complement, also used for representing negative numbers.
• Sign and magnitude represents numbers with the left-most bit indicating the sign and the remaining bits indicating the magnitude.
• Hexadecimal is a base-16 system using digits 0-9 and letters A-F.
• A memory dump is a snapshot of memory content.
• Binary-coded decimal (BCD) represents each decimal digit with a 4-bit binary code.
• ASCII is a 7-bit character encoding standard for text.
• Unicode supports multiple languages using 16-bit or 32-bit encoding.

Multimedia

• Bit-map images use pixels to represent images.
• A pixel is the smallest addressable element in an image.
• Colour depth is the number of bits used to represent the colour of a single pixel.
• Resolution is the number of pixels in an image, expressed as width × height.
• Vector graphics use mathematical formulas to represent shapes.
• Sound representation involves sampling rate, measured in samples per second.
• Bit depth represents the number of bits per audio sample.
• Video representation uses frame rate, measured in frames per second.
• Compression reduces file size, and can be lossless or lossy.
• Lossless compression restores the exact original data upon decompression.
• Lossy compression discards some data to achieve smaller file sizes, as seen in JPEG, MP3, and MP4 formats.

Unit 2: Communication and Networking

Network Types

• A LAN (Local Area Network) covers a small area, such as a building.
• A WAN (Wide Area Network) covers a large geographical area.
• A MAN (Metropolitan Area Network) covers multiple buildings in a city.
• A WLAN (Wireless LAN) uses wireless connectivity instead of cables.

Networking Devices

• A router connects different networks.
• A switch sends data packets only to the intended recipient.
• A hub broadcasts data packets to all connected devices.
• A modem converts digital signals to analogue and vice versa, enabling network communication.
• A NIC (Network Interface Card) connects a device to a network.
• A repeater boosts weak network signals.

Network Topologies

• In a bus topology, all devices share a single cable.
• In a star topology, all devices connect to a central switch.
• In a mesh topology, devices connect to multiple others for redundancy.
• A hybrid topology is a combination of multiple topologies.

Internet Concepts

• IPv4 addresses use 32-bit addresses (e.g., 192.168.1.1).
• IPv6 addresses use 128-bit addresses, providing a larger address space.
• The Domain Name System (DNS) converts domain names into IP addresses.
• Bit streaming can be on-demand, like Netflix, allowing streaming when requested.
• Real-time bit streaming is used for live events.

Unit 3: Hardware

Memory Types

• RAM (Random Access Memory) is volatile and stores active data.
• ROM (Read-Only Memory) is non-volatile and stores essential data.
• DRAM (Dynamic RAM) needs refreshing.
• SRAM (Static RAM) is faster and does not require refreshing.

Storage Types

• An HDD (Hard Disk Drive) uses spinning disks and is generally slower.
• An SSD (Solid State Drive) uses flash memory and is faster.
• Optical storage (CD/DVD/Blu-ray) uses laser technology.

Input/Output Devices

• Laser printers use toner, providing fast and high-quality printing.
• Inkjet printers use liquid ink, making them suitable for photos.
• 3D printers build objects layer by layer.
• LCD displays require backlighting.
• OLED displays feature self-illuminating pixels, giving better contrast.
• Sensors measure environmental data like temperature and pressure.

Unit 4: Processor Fundamentals

Von Neumann Architecture

• A single memory is used for both programs and data.
• The Control Unit manages instructions.
• The Arithmetic Logic Unit (ALU) performs calculations.
• Registers are small storage areas inside the CPU.

Buses

• The address bus carries memory addresses unidirectionally.
• The data bus carries actual data bidirectionally.
• The control bus carries control signals.

Fetch-Execute Cycle

• Fetch gets the instruction from memory.
• Decode understands the instruction.
• Execute performs the operation.

Processor Performance Factors

• Clock speed determines the number of instructions processed per second; higher speed means more instructions.
• Cache memory stores frequently used data for faster access.
• The number of cores enables parallel processing.

Unit 9: Algorithm Design and Problem Solving

Computational Thinking

• Abstraction involves ignoring unnecessary details.
• Decomposition involves breaking down problems into smaller parts.
• Pattern recognition involves identifying similarities among problems.

Algorithm Techniques

• Structured English uses simple step-by-step descriptions.
• Flowcharts use diagrammatic representations of algorithms.
• Pseudocode uses a code-like representation of algorithms.

Control Structures

• Selection (IF, CASE) involves making decisions in algorithms.
• Iteration (FOR, WHILE, REPEAT-UNTIL) involves repeating actions.

Unit 10: Data Types and Structures

Data Types

• Integer represents whole numbers.
• Float represents decimal numbers.
• Boolean represents True/False values.
• String represents text data.

Data Structures

• Arrays are fixed-size collections of elements.
• Records contain multiple data fields.
• Stacks operate on a LIFO (Last In, First Out) principle.
• Queues operate on a FIFO (First In, First Out) principle.
• Linked Lists consist of elements that point to the next element in the list.

Sorting & Searching

• Linear search checks each element one by one.
• Bubble sort compares adjacent elements and swaps them if necessary.

This lesson covers data representation methods like binary, one's and two's complement, and hexadecimal. It also discusses multimedia concepts, including bit-mapped images and color depth. Character encoding standards ASCII and Unicode are also covered.