Units

• Units of Data Storage

  • Bit
  • Nibble (4 Bits)
  • Byte (8 Bits)
  • Kilobyte (1024 Bits)
  • Megabyte (1024 Kilobytes)
  • Gigabyte (1024 Megabytes)
  • Terabyte (1024 Gigabytes)
  • Petabyte (1024 Terabytes)
• Computers use binary because computer systems consist of billions of transistors which are switches that only contain 1 value, 1 or 0. Therefore all data must be represented in this way
• Hexadecimal

  Ranges from 00 to FF, a Base-16 numerical system, running from 1-9, then A-F
• Binary ranges from 0000 0000 to 1111 1111 (0 to 255)
• Binary digits

  Each digit, from left to right is valued to 2^n, where n is the digit, starting from 0
• Adding binary digits

  1. 0 + 0 = 0

  2. 1 + 0, or 0 + 1 = 1

  3. 1 + 1 = 10, with the 1 being added to the column to the left

  4. 1 + 1 + 1 = 11, with the 1 being added to the column to the left
• An overflow error is when we are adding 2, 8-bit binary sequences and it reaches a value over 255 (8-bit limit). This would result in an overflow error as it is too large
• Binary shift

  Cross off the number of digits on the end of the binary sequence that we are shifting by, in the direction it asks to shift