Bits and bytes
Physical representation
"Bits is bits": 10101100011
bit: single binary digit, value 0 or 1
nybble: 4 bits
byte: 8 bits
halfword: 16 bits (2 bytes)
word: 32 bits (4 bytes); can vary with machine architecture
32-bit architecture in this class
doubleword: 64 bits (8 bytes)
bit string: any number of consecutive bits (11 bits in example)
Logical representation
bits + context = information
consider bit string with k bits (k = 6)
b5 b4 b3 b2 b1 b0
0 1 1 0 1 0
value:
b5 * 25 b4 * 24 b3 * 23 b2 * 22 b1 * 21 b0 * 20
0 * 32 1 * 16 1 * 8 0 * 4 1 * 2 0 * 1
0 16 8 0 2 0
16 +   8 +   2  =   26ten
unsigned binary representation
least significant bit (lsb): b0
most significant bit (msb): bk-1