1.2.4

• Binary addition

  • 0 + 0 = 0
  • 1 + 0 = 1
  • 0 + 1 = 1
  • 1 + 1 = 1 0
  • 1 + 1 + 1 = 1 1
• Convert hex to denary:

  8 7

  1000 0111

  135
• Convert denary to hex:

  106

  0110 1010

  6 A
• The bit with the largest value (the left-most bit) is called the most significant bit
• The bit with the smallest value (the right-most bit) is called the least significant bit
• When doing a binary shift gaps at the beginning or end are filled with 0s
• Left shifts multiply a binary number. For every place shifted left, the number is doubled.
• Right shifts divide a binary number. For every place shifted right, the number is halved.
• Left shifts can cause overflows, and right shifts can cause bits to 'drop off the end'. Bits dropping off or overflowing can lead to loss of accuracy/data.
• Character sets are collections of characters that a computer recognises from their binary representation. They contain all the characters that are recognised and can be represented by the computer hardware and software.
• Each ASCII character is given a 7 bit binary code - this means it can represent a total of 128 different characters. And extra bit (0) is added to the start.
• Extended ASCII uses 8 bits allowing or 256 different characters to be represented. Allows for some special characters from foreign languages to be represented.
• Unicode is now 24 bits with sufficient characters for all written languages, historical scripts and modern characters such as emojis. Provides for more than 16 million characters.