What is a "host process"? What is "Machine-dependent absolute address" when referring to process rank?

[wgropp]

Section 9.1.2, p453 (MPI40) in describing the "MPI_HOST" predefined attribute key, calls this the "host process rank". This dates from the very, very early days of message passing systems, when some systems had a separate "host" computer and a process running on it, which might be part of the MPI job. I do not believe any system does this any more (so we might also want to deprecate MPI_HOST), but in any event, "host process" is undefined in the MPI standard.

Related to this, in 7.2.4 on page 316 (MPI40), is

MPI does not specify the correspondence between the process rank in MPI_COMM_WORLD and its (machine-dependent) absolute address.

What is a "(machine-dependent) absolute address"? Elsewhere in the standard, absolute addresses refer to the memory address space. Yes, I know what is intended here - but the standard should be precise and clear.

(Originally found in translating MPI 2.2 into Japanese)

[wesbland]

In fact, we do have an issue in progress to deprecate MPI_HOST: #57

[wesbland]

I think the part in Chapter 9 can be a duplicate of #57. For the rest of it, I'll hand this to the Chapter 7 CC: @GuillaumeMercier

[wesbland]

This wasn't read at the December 2022 meeting. The last opportunity for MPI 4.1 is to have it ready at the March 2022 meeting (and it needs to "pass" the reading).

@GuillaumeMercier Are you (or is someone else) planning to push this forward or should we move it out of the plan for MPI 4.1?

[GuillaumeMercier]

I have to think about this one.