Thanks John --

Yay for Henry Baker! (And don't forget that Carl Hewitt was part of 
the braintrust behind this stuff -- and also Marvin Minsky had the 
original idea for a copying multiple address space GC some years 
before this, and starting this tradition of thought at MIT).

Cheers,

Alan

At 12:12 PM -0700 8/21/03, John W. Sarkela wrote:
>Hi all,
>
>I'm about 1k messages behind on the list, but this caught my eye. 
>Having been around when ephemerons were introduced at Digitalk, I'll 
>advance the following historical notes.
>
>VSE had ephemerons prior to the ParcPlace merger. It was Digitalk 
>technology, not ParcPlace.
>
>IIRC, George Bosworth was inspired by a paper on guardians. I don't 
>have the reference handy, but I believe that it was in an ACM 
>SIGPLAN publication. This would have been very early in the 90's.
>
>(with regard to Nevin's statements about the ownership of VSE IP)
>Seagull did not get all Digitalk/VSE technology, they only purchased 
>the VSE technology directly related to the PARTS for Java product. 
>To the best of my knowledge, Digitalk->PPD->Objectshare->Cincom have 
>always held the rights to VSE Smalltalk technology.
>
>As for prior art, let us not forget the seminal work of Henry Baker. 
>Some of the most important ideas about garbage collection I trace 
>back to his ground breaking work.
>
>Cheers,
>
>John Sarkela
>:-}>
>
>On Saturday, August 9, 2003, at 01:45 PM, Alan Kay wrote:
>
>>Patents, oh my ....
>>
>>Check out Feldman's Associative Triples (and Rovner's 
>>implementation of them for a swapping device) from the mid60s, 
>>HASHCONS and other similar schemes for Lisp and later, some of the 
>>early Smalltalks for various other ways of achieving similar useful 
>>results ....
>>
>>As is so often the case, prior art is ... well ... prior.
>>
>>Cheers,
>>
>>Alan
>>
>>At 5:04 PM +0200 8/9/03, Roel Wuyts wrote:
>>>Ask Eliot, since he implemented it for VisualWorks. I can imagine 
>>>that either (a) the patent is now Cincom's or (b) the patent is 
>>>not Cincom's, and then they'll know about it (after all, they have 
>>>enough lawyers to check this out.
>>>
>>>On Saturday, Aug 9, 2003, at 15:35 Europe/Zurich, Andreas Raab wrote:
>>>
>>>>>I have a feeling PPS got a patent for the idea.
>>>>
>>>>Any idea where to find this patent? I'm not too concerned about this patent
>>>>(if it exists) as there are various other ways in which the same effect
>>>>(being able to attach external properties to objects) can be 
>>>>achieved. Using
>>>>ephemerons is just a very convenient way of doing it as you don't have to
>>>>worry much about the relations in the graph of objects.
>>>>
>>>>Cheers,
>>>>   - andreas
>>>>
>>>>
>>>Roel Wuyts Software Composition Group
>>>roel.wuyts at iam.unibe.ch                       University of Bern, 
>>>Switzerland
>>>http://www.iam.unibe.ch/~wuyts/
>>>Board Member of the European Smalltalk User Group: www.esug.org
>>
>>
>>--


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