I don’t know who to address this to, so I will ask you all. Is there someone out there who worked on the T9000 protected mode system?
I picked up a copy of "THE T9000 TRANSPUTER HARDWARE REFERENCE MANUAL” at
and looked at the communication instructions in, out, etc. (p 95). They were all marked P (Instruction not allowed in P-process). By contrast, move was marked M (Invalid memory-address for P-process), as were ldnl, stl, stnl, etc. Thus, the latter are legal given good addresses, and the former are not legal even if addresses are good, despite the famous CSP equivalence of
b := a
chan c :
c ! a
c ? b
Why are the communications illegal? Was it because only one "current process” is allowed, or was it too hard to keep control over virtual memory while waiting for the second process, or was development effort too great for something which does not exist in C-language user-space? Was communication off-loaded to the L-process belonging to that P-process, or was it just not modeled?
By the way, thank you everyone who helped me to a copy of Michael Poole’s ETC paper in WoTUG-21. The book arrived, and has several other treasures besides ETC. For instance, “An optimizing multiprocessor occam system for the PowerPC” has true interrupt-level high priority, simple edge links, and even an extension of the configuration (.PGM) files!