Comment Re:direct CPU-CPU interconnects; Transputer? (Score 4, Informative) 366
Transputers had 4 HW links -- those are probably the easiest part to replicate in current processors.
The difficult part is the threading model: Transputers had their own thread model. Scheduler was hardwired in silicon, together with a couple of dedicated instructions. SW could not tell the difference between a local and a remote communication. Efficient, but not very flexible in terms of OS architecture.