Octal
<mathematics> Base 8.
A number representation using the digits 0-7 only, with the right-most digit counting ones, the next counting multiples of 8, then 8^2 = 64, etc.
For example, octal 177 is digital 127:
digit
weight
value 1
8^2 = 64
1* 64 = 64 7
8^1 =
8
7*
8 = 56 7
8^0 =
1
7*
1 =
7 --- 127
Octal system used to be widespread back when many computers used 6-bit bytes, as a 6-bit byte can be conveniently written as a two-digit octal number.
Since nowadays a byte is almost always 8-bit long the octal system lost most of its appeal to the
hexadecimal system.
For a brief discussion on the word `octal' see
hexadecimal.
