At PDP, the PDP-5, PDO-8 and PDP-12 were 12-bits and the PDP-6 and PDP-10 were 36 bit, all of which are multiples of both 3 and 4
Memory was expensive at the time, so I would guess most of them had 6-bit character sets. That must have made octal a popular choice.
I think https://en.wikipedia.org/wiki/Hexadecimal#History_of_written... shows the notation for hex wasn’t settled upon. I think that’s an indication of its rarity (go read it to learn which version was deemed “ridiculous” :-) )
At PDP, the PDP-5, PDO-8 and PDP-12 were 12-bits and the PDP-6 and PDP-10 were 36 bit, all of which are multiples of both 3 and 4
Memory was expensive at the time, so I would guess most of them had 6-bit character sets. That must have made octal a popular choice.
I think https://en.wikipedia.org/wiki/Hexadecimal#History_of_written... shows the notation for hex wasn’t settled upon. I think that’s an indication of its rarity (go read it to learn which version was deemed “ridiculous” :-) )