Computer Basics Notes

Basic Computer Components

  • Power Supply
  • Microprocessor (CPU) + Fan
  • RAM
  • Video Card
  • Sound Card
  • Casing
  • CD-DVD
  • Motherboard
  • Hard Disk

How Computers Work

  • Computers work similarly to the human brain.
  • Eyes (Input) translate light to brain signals.
  • Brain (CPU) processes information using memory.
  • Mouth (Output) translates brain signals to voice.

CPU and Storage

  • CPU: The "brain" that performs calculations.
  • Storage: Stores data; needs to be fast to match CPU speed.
    • RAM: Fast, expensive, small size.
    • Hard Disk: Slow, inexpensive, large size.
  • Data is loaded from Hard Disk to RAM for faster CPU processing.
  • Opening too many programs slows down the computer when RAM is full, forcing the CPU to use the slower Hard Disk.
  • Computers have input and output devices.

Hardware vs. Software

  • Hardware: Physical components (CPU, RAM, Hard Disk).
  • Software: Programs that instruct the hardware.
  • Application Software: Fulfills specific needs.
  • System Software: Runs the computer's hardware and provides a platform for applications.
  • Programming Languages: Used to create applications.

Binary Language

  • Computers use binary language (0 and 1).
  • Each letter is represented by 8 binary digits (8-bit).
  • Example: A = 01000001

Counting Systems

  • Humans use a 10-digit system (0-9).
  • Computers use binary (0 and 1).
  • 1 bit gives 2 possibilities.
  • 2 bits give 2^2 = 4 possibilities.
  • 3 bits give 2^3 = 8 possibilities.
  • 10 bits give 2^{10} = 1024 possibilities.

Number Systems

  • Decimal (Base 10): Digits 0-9.
  • Binary (Base 2): Digits 0-1.
  • Octal (Base 8): Digits 0-7.
  • Hexadecimal (Base 16): Digits 0-9, A-F (A=10, B=11, C=12, D=13, E=14, F=15).

Converting Binary to Decimal

  • Multiply each digit by its respective power of 2 and sum the results.
  • Example: 11010 (binary) = (1 x 2^4) + (1 x 2^3) + (0 x 2^2) + (1 x 2^1) + (0 x 2^0) = 16 + 8 + 0 + 2 + 0 = 26 (decimal)

Converting Decimal to Binary

  • Subtract the largest possible power of 2 from the decimal number, record the power, and repeat until the remainder is zero.
  • Place 1s in the binary result at the recorded power positions and 0s elsewhere.

Special Powers of 2

  • 2^{10} (1024) = Kilo (K)
  • 2^{20} (1,048,576) = Mega (M)
  • 2^{30} (1,073,741,824) = Giga (G)

How Computers Store Data

  • Images: Broken into pixels, each with a color.
  • Audio: Sampled thousands of times per second.
  • Videos: Made of pictures and music.

Networks

  • Computers communicate through networks.
  • Network cards transmit data (0s & 1s) as signals.

Storage Measuring Units

  • Bit: Basic unit (0 or 1).
  • Byte: 8 bits.
  • KB: Kilobyte = 1024 Bytes.
  • MB: Megabyte = 1024 KB.
  • GB: Gigabyte = 1024 MB.
  • TB: Terabyte = 1024 GB.

CPU Speed

  • Measured in Hertz (Hz).
  • MHz: Megahertz = 1 Million Hz.
  • GHz: Gigahertz = 1 Billion Hz.

Data Transfer Speed

  • Measured in bits per second (bps).
  • Mbps: Million bits per second.
  • Gbps: Billion bits per second.