Data Representation and Types Quiz

1. Data Representation

• Binary system uses 0s and 1s to represent all computer data
• Decimal to binary conversion: Repeatedly divide by 2, record remainders
• Binary to decimal conversion: Multiply each binary digit by 2 raised to its position index and sum
• Hexadecimal (base-16) simplifies binary representation using 0-9 and A-F
• Binary to hexadecimal conversion: Group binary digits into sets of four
• Hexadecimal to binary conversion: Convert each hexadecimal digit to its 4-bit binary equivalent
• Decimal to hexadecimal conversion: Repeatedly divide by 16, record remainders
• Hexadecimal to decimal conversion: Multiply each digit by 16 raised to its position and sum
• Hexadecimal applications include memory addresses, color codes (HTML/CSS), and MAC addresses

1.2 Data Types

• ASCII (American Standard Code for Information Interchange): Represents characters using 7 or 8 bits
• Unicode: Represents every character with a unique number, supporting international languages
• Images are made of pixels, representing single colors, with higher resolution having more detail
• Higher color depth means more colors used for a pixel. 1 bit = black/white, 24-bit= 16 million colors
• Sound is sampled: measuring amplitude at regular intervals
• Sample rate (Hz) measures samples per second
• Bit depth affects sound quality (higher is better for quality)

1.3 Data Storage

• Bit: Binary digit (0 or 1)
• Nibble: 4 bits
• Byte: 8 bits
• KB: 1024 bytes
• MB: 1024 KB
• GB: 1024 MB
• TB: 1024 GB
• Data Compression:
  • Lossy compression permanently removes some data (e.g., JPEG)
  • Lossless compression does not lose any data (e.g., ZIP)

2. Data Transmission

2.1 Transmission Modes

• Serial Transmission: Bits sent one after another over a single channel. Suitable for long distances, less interference (e.g., USB).
• Parallel Transmission: Multiple bits sent simultaneously over multiple channels. Faster, but not suitable for long distances due to signal skew (e.g., internal computer transfer)

2.2 Synchronization

• Asynchronous Transmission: Data sent with start/stop bits for each byte, allowing the receiver to understand when bits start/end. Used in serial ports.
• Synchronous Transmission: Data sent in a continuous stream, synchronized by a clock signal. More efficient for high-speed transmission (e.g., network communications)

2.3 Error Detection

• Parity Checking: Even or odd number of 1s to detect errors, but incomplete error detection
• Checksums: Summing all bytes, sending the value; receiver recalculates to verify integrity.
• Cyclic Redundancy Check (CRC): More complex method using polynomial division; detects burst errors more effectively.

2.4 Data Transmission Security

• Encryption protects data during transmission from unauthorized access
  • Symmetric: Same key for encryption/decryption
  • Asymmetric: Public key for encryption, private key for decryption

3. Hardware

3.1 Central Processing Unit (CPU)

• Control Unit (CU): Manages instruction execution.
• Arithmetic Logic Unit (ALU): Performs arithmetic and logic.
• Registers: Fast storage locations in the CPU.
• Program Counter (PC): Holds next instruction address.
• Accumulator: Stores intermediate results.
• Fetch-Execute Cycle: Fetches, decodes, executes instructions

3.2 Memory

• RAM (Random Access Memory): Volatile memory for currently used data/programs. Data lost when power off; read and write;
• ROM (Read-Only Memory): Non-volatile memory for essential system instructions. Data retained without power, stores firmware/boot programs.

3.3 Input and Output Devices

• Input: Keyboard, mouse, scanner, microphone.
• Output: Monitor, printer, speakers, projector.

3.4 Storage Devices

• Magnetic Storage: Hard Disk Drives (HDDs): Large capacity; mechanical parts, susceptible to wear.
• Solid-State Drives (SSDs): Flash memory, no moving parts; faster access, more durable
• Optical Storage (CDs, DVDs, Blu-rays): Use lasers to read/write data; software, music, movies distribution

3.5 Emerging Technologies

• 3D Printing: Rapid prototyping, customized production (manufacturing, medicine, architecture).
• Artificial Intelligence (AI): Simulation of human intelligence by machines (virtual assistants, autonomous vehicles, data analysis). Considerations include ethical implications and job displacement.