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
>
>
> -- 
>