and here are a few more (mostly home computers)
Anyway, this architecture is actually quite similar to the design of modern GPUs.
AVR, on the other hand, is a Harvard architecture, as the program does not exist in the same address space as data. It is possible to read from program memory, but only using special-purpose instructions. I believe the same goes for PIC, but I'm not as familiar with it.
The description of this machine isn't quite detailed enough for me to say for sure, but I think it may be a Von Neumann architecture, if only because I don't see any labeled instruction memory. I may be misunderstanding how it's supposed to work, though.