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From: mike@ames.arpa (Mike Smithwick)
Newsgroups: comp.unix.wizards
Subject: kludging up the page tables
Message-ID: <2416@ames.arpa>
Date: Tue, 28-Jul-87 18:40:15 EDT
Article-I.D.: ames.2416
Posted: Tue Jul 28 18:40:15 1987
Date-Received: Thu, 30-Jul-87 02:27:52 EDT
Reply-To: mike@ames.UUCP (Mike Smithwick)
Distribution: na
Organization: NASA Ames Research Center, Moffett Field, Calif.
Lines: 31
Keywords: Ollie North+Fawn Hall
Summary: aack! phfpptt!

[Powdermilk biscuits! Heavens they're tastey!]


Ok all of you wizards out there, donn your turbans or spiked hats, grab
yer wand and make some incantations, as I humbly bow before the great
throne of Un*x wisdom.  

I am trying to implement a really crude shared memory scheme for a one
time only demonstration. We are needing to have shared common blocks in
an, pardon the expression, FORTRAN, helicopter model. That is, the model 
will be split among two different processes. Normal shared memory 
won't work since you can only access it via pointers, and FORTRAN doesn't
know about them. So I need to be able to have the processes access thee
same data page invisible to each other. What I've tried to do is to 
take the physical page # of one process, and stuff it into the data pte
of the other process which points to it's own data page.

After the page-twiddle on the client, I acccess the data in the normal fashion
and it is the same as before. i.e.,the addresses are  not being redirected
to the new page.

Yes, the processes are not swapped out. I know thhat I can trash the system.
I do bring back the original page when done.

So, I would appreciate any help. Complaints about  my method may be
directed to /dev/null.
-- 
				   *** mike (powered by M&Ms) smithwick ***
"ever felt like life was a game, and 
someone gave you the wrong instruction book?"
[discalimer : nope, I don't work for NASA, I take full blame for my ideas]