topic 2: data

topic 2: data

1. units

   • data stored in binary
   • binary digit is bit
   • 8 bits = 1 byte
     • 1,024 bits = 1 kilobyte (KB)
       • 1024 kilobytes = 1 megabyte (MB)
         • 1024 megabytes = 1 gigabyte (GB)
           • 1024 gigabytes = 1 terabyte (TB)
             • 1024 terabytes = 1 petabytes (PB)
   • half byte = nibble

2. denary

   • base 2
   • represented in 0,1,2,3,4,5,6,7,8,9
   • subtract biggest value from number

3. binary

   • base 10
   • binary place values - 128,64,32,16,8,4,2,1
   • represented in 1 and 0
   • binary addition
     • rules
       • 0 + 0 = 0
       • 1 + 0 = 1
       • 1 + 1 = 10
       • 1 + 1 + 1 = 11
   • binary shifts
     • multiplication - moves digits to left
       • multiple 2 = 1 place left
       • multiple 4 = 2 places left
       • multiple 8 = 3 places left
     • division - moves digits to right
       • divide 2 = 1 place right
       • divide 4 = 2 places right
       • divide 8 = 3 places right

4. negative numbers

   • left most value is most significant bit (MSB)
   • at start, 0 is positive
   • at start, 1 is negative
   • two's complement
     • MSB is negative value

5. shifts

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