Not a bad artcle, but it had a number of minor errors, which I found irritating.
They should have gotten an expert to proof it.
Sure - but usually these are way more bad than good. Usually way too much urban legend, so I'm thrilled to see the 11 kept alive.
And a tip of the hatly hat for getting this:
Although the ++ and - operators in C are equivalents of DEC and INC
instructions, they were inspired by an addressing mode in the PDP-7.
As I said, the authors seem to have done a little homework, although I was under the impression ??Ken?? had created them for B independently (which, of course, was first on the PDP-7). The ++/-- for increment and decrement was just a nice notation since they are such a common occurrence in real code, it's handy to have. But, I did not think the PDP-7 ISA includes addressing modes in the same manner as the 11. I'm probably confused, but I thought PDP-7 is a very simple instruction (and small) with an AC, Link/Indirection and a PC - it reminded me of the PDP-8 more than anything else [although, IIRC it could do both 1's complement and 2's - depending the type of AND instruction].