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From: mcvax!inmos!zenith@uunet.UU.NET (Steven Zenith)
Newsgroups: comp.os.research
Subject: Re:  Comp.OS.Research (Nov_20_10.54)
Message-ID: <5608@saturn.ucsc.edu>
Date: 19 Nov 88 19:15:59 GMT
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Re posting from from: dls@mace.cc.purdue.edu (David L Stevens)
Date: 19 Nov 88 19:15:59 GMT


>	Suppose you have a network of workstations and you map the virtual
>address space of each by page faults that result in network requests to one
>or more servers. I'm looking for algorithms to manage the "global" virtual
>address space of the network, and pieces in use by the individual machines.
>
>	Applications: shared libraries, shared "in core" binaries, shared
>"in core" filesystem data, inter-machine process migration, etc etc.

This appraoch to global addressing seems like incredibly hard work and 
fraught with difficulties (maintaining integrity etc..). If you really
need this kind of solution in the mentioned application areas, I
would strongly suggest you look at the `Linda' work done at Yale.
The first paper to read is:

Generative Communication in Linda by David Gelernter.
ACM Transactions on Programming Languages and Systems,
Vol. 7 No. 1, January 1985, PAges 80-112.

The Linda solution presents the application with a kind of `global
associative memory' in which data resides. The guys at Yale have
a number of `off the peg' implementation solutions (see Nich 
Cariero [not sure spelling is correct] thesis on Linda Implementation
submitted this year [I'd love a copy of this please!]).

From a systems point of view Linda provides powerful solutions to many
of the other problems confronted in a distributed environment. But you
didn't hear this from me (!)! The concept of generative communication
in particular simplifies the problem of resource allocation and
recovery (won't someone please do some formalisation of this work, then I
might be able to justify using it!). If you haven't yet had a brief summary 
overview of Linda posted I'd be happy to oblige.


 *  Steven Ericsson Zenith     Snail mail: INMOS Limited, 1000 Aztec West,
 |    zenith@inmos.uucp                    Almondsbury, Bristol BS12 4SQ. UK.
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      ** All can know beauty as beauty only because there is ugliness **