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Re Re: :zz: "!@#$% General DATA solution impossible

Hi Mark--

The problem isn't concurrency.  The problem is the
 complex tissue structure of ZigZag.  If each process
 is just creating an independent file or well-expected datum,
 there's no problem.  However, each process in a parallel ZZ
 could rip the tissue in another direction.

Another way to put it: data in ZigZag is in some sense global.

A *non-general* solution will allow each process to create
 its own unconnected cell, rank, grid, etc.  The problem is
 the connections and keeping them from messing each other up.

A wonderful image just occurred to me: a lot of berserk
 sewing machines on wheels, stitching everything in your
 closet together chaotically.

Best, T

At 11:58 AM 4/6/99 -0700, you wrote:
>At 02:07 AM 4/3/99 , Ted Nelson wrote:
>>You said:
>>>I don't presently see any simple solution for the general case, except
>>>to note that these are traditional problems of parallelism ...
>>The reason is that if we aren't seriously simplifying
>> in some original way, maybe we shouldn't be doing it.
>E's concurrency control model, derived from Actors, FCP, and Joule 
>http://www.agorics.com/joule.html but reconciled with sequential 
>programming, is a solution to the general concurrency control problem that's 
>much simpler and more robust than the thread/locking model.  Unfortunately, 
>I haven't adequately documented this model yet, but see 
>"http://www.erights.org";, especially 
>"http://www.erights.org/elib/concurrency/index.html"; and 
>"http://www.erights.org/elib/concurrency/vat.html";.  My guess is that all 
>this would apply perfectly well to zigzag.
>	Cheers,
>	--MarkM
Theodor Holm Nelson, Visiting Professor of Environmental Information
 Keio University, Shonan Fujisawa Campus, Fujisawa, Japan
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