(That's the PDP-10 instruction set documentation, but the PDP-6's instruction set was essentially identical).
I never wrote PDP-6 code but wrote a lot of PDP-10 code and the byte instructions were used heavily. In particular characters were commonly six or seven bits wide so string manipulation used byte pointers and was quite fast, but they were also good for packed arrays of all sorts of sizes.
You mean like the famous PDP-6 from 1964? The width of a byte was variable and could be as small as 1: http://pdp10.nocrew.org/docs/instruction-set/Byte.html
(That's the PDP-10 instruction set documentation, but the PDP-6's instruction set was essentially identical).
I never wrote PDP-6 code but wrote a lot of PDP-10 code and the byte instructions were used heavily. In particular characters were commonly six or seven bits wide so string manipulation used byte pointers and was quite fast, but they were also good for packed arrays of all sorts of sizes.