bartc <b...@freeuk.com> writes: > On 11/05/2018 01:25, Marko Rauhamaa wrote: >> Chris Angelico <ros...@gmail.com>: >> >>> Octal makes a lot of sense in the right contexts. >> >> I think octal is a historical relic from a time when people weren't yet >> comfortable with hexadecimal. > > It's a relic from when machines had word sizes that were multiples of > three bits, or were divided up on 3-bit boundaries.
It got into C via B and B was often used on machine with a word size that was a multiple of three. But octal was very useful on 16-bit PDP-11s which is probably why it was kept. The PDP-11 has 8 registers and uses 3 bits to specify the addressing mode and many instructions use the top bit to indicate a variation such as word or byte operation. The result is that you'd never choose to use hex to look at PDP-11 code. That familiarity with octal must have played a bit part in deciding to include it in C. -- Ben. -- https://mail.python.org/mailman/listinfo/python-list
