Is there a Unix equivalent of VMS Mapped Global Sections?

[Todd Goodman]

I've recently been asked by someone who has the task of porting to Unix a large
system written to run on VMS what the Unix equivalent of VMS's Mapped Global
Sections are.  The system uses very large Mapped Global Sections (larger than
the available physical memory).

I mentioned shared memory to him, but he was concerned since there was no
backing store to a file (as with Mapped Global Sections) and because shared
memory is shared real memory (I think this is true;  Is it?) instead of virtual
memory.

I personally believe that they would be better served by looking at what they
really want to do and then reimplementing in a more traditional Unix method.

Barring reimplementation, what are people's suggestions?  It seems that if he
wants to stick with the shared virtual memory methodology that he will have to
implement something himself.  Is this the case?

Discussions related to any of the common Unix flavors will be appreciated
since I don't believe they've picked a specific flavor (but will probably go
with SunOS).

				Thanks in advance,

					Todd Goodman
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