Yeah, so it's a wrong thing in 2015 where the only significant use of octal is in unix permissions which themselves are only octal because of PDP-7/8. The 9/18

Yeah, so it's a wrong thing in 2015 where the only significant use of octal is in unix permissions which themselves are only octal because of PDP-7/8. The 9/18/36-bits architectures have lost but octal conventions of C was made on the PDP-7 (18 bits) and until the early 1980s, 36-bit machines were commercially available (PDP-10.)