The external specifications of the Gnosis kernel suggest multiple tightly coupled {shared main storage} CPU's. The kernel as presently coded can use only one CPU. We have estimated that two man years and two calendar years would suffice for the kernel modifications to support several CPU's.

This project takes only local invention because we had multiprocessors in mind from the beginning.

Loosely coupled processors are another question. If several machines were connected together by CTCA {channel to channel adaptors} then the kernel could be taught to "shoulder tap" when it went for a page. Shoulder tapping is what a 370 CPU does to the cache of a fellow tightly coupled CPU when it wants some data that the other may hold.

This is not a very complex implementation project; the question is what set of applications would tolerate the extra expense and how do we manage the choice of which CPU to run the job on.

I think that the application would have to play some role in managing the segregation that would be required to avoid excessive page and node shuffling.