[self-interest] dSelf - A distributed Self for JVM Platforms
lourenci at lsi.usp.br
Fri Mar 16 16:03:18 UTC 2001
Robert Tolksdorf wrote:
I was not able to open your dSelf documents?
What jar means? Is it ps, pdf, doc. What is it?
I work in a Sun station/.
> [being new to the list, I am not sure about conventions - if this
> should be answered directly, please tell]
> Jecel Assumpcao Jr
> > Wow! Congratulations on this excelent work!
> > At a presentation I gave on Monday I was asked if any academic groups
> > were working on Self implementations and I said "no". I am very glad
> > that I was wrong about that.
> > After reading the dself.pdf I would like to make some slight
> > corrections. There were, in fact, previous papers on distributed Self
> > but they were written in Portuguese and so wouldn't have been of much
> > help to you. My key insight in the later papers was that not only
> > primitive objects but any immutable objects could be copied without
> > affecting the execution semantics. My system is a multiuser one and any
> > any given "session" most objects (those belonging to other users) are
> > read-only and can be replicated instead of using remote references.
> Have you tried to push the papers through the Altavista Babelfish?
> Concerning replication: Right now, there are two sorts of things in
> dSelf, the one are references, the others are primitive objects (such
> as the number 1). The primtive objects are located at _every_ dSelf
> VM, so in some sense, they are in fact replicas (one can also say that
> eg. the Java-standard classes are replicated on every JVM). Of course,
> true replica need some sort of consistency management, which we
> currently do not need, as primitve objects are immutable (cf. the java
> standard classes). There is going to be another diploma theses that
> deals with the issue. In fact, the work on it should start this week.
> My view is that we should introduce something like in Replicated Obliq
> by MacIntyre, where remote, replicated and simple (ie. primitive)
> objects are distinguished and the environment offers means to change
> the "class" of objects along those three kinds.
> > Your use of "<-" versus "=" in slot declarations seems strange. I don't
> > think that the stack examples are quite right: you change slots defined
> > with "=" ("parent", for example). You use the "clone" method but it is
> > not defined anywhere (you don't mention the traditional "traits
> > clonable" object, for example).
> we should have mentioned (and might add a footnote), that these
> examples use a pseudo code. The reason for that was to show simple
> code instead of lots of _addslots messages whose explanation would
> have cluttered the flow of the text.
> > Several of the things you mention as missing in dSelf were actually
> > dropped in Self 3.0. I found it strange that you wrote that Self
> > doesn't have local methods, but I just tried it in Self 4.1.2 and did
> > indeed get the error: "syntax error - local slots not implemented yet".
> > How strange.
> We took 4.x as reference. The assumption of downward compatibilty
> seems to be quite wrong...
> > In tinySelf 1 I explored parallel (but not distributed) execution in
> > Self but got stuck in trying to lock things automatically. It is not an
> > easy problem to solve.
> We currently have this ad-hoc solution with locking objects. The
> mentioned diploma-thesis shall also deal with the issue of finding a
> suited model for concurrency in self and implementing it. in dSelf, we
> have implicitly concurrency by two people (or a shell) starting two
> dself-VMs that then do run concurrently, although there is no forking
> within a dself vm.
> > Once again: good work!
> Thanks. [I include Kai in the cc, as he did the implementation and a
> lot of design decisions]
> Ciao Robert
> > -- Jecel
> > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> Dr.-Ing. Robert Tolksdorf | Technical University Berlin _______ _
> mailto:tolk at cs.tu-berlin.de | FB 13 - FLP/KIT - FR 6-10 (_ _ | |
> http://www.cs.tu-berlin.de/~tolk | Franklinstr. 28/29 | | | | |
> tel: +49-30-314-25184 (FR6071) | D-10587 Berlin / Germany `-' `---'
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
| Albertina Lourenci |
| PhD in Architecture and Urbanism |
| post-doctorate researcher |
| Laboratory of Integrated Systems University of Sao Paulo |
| Avenida Professor Luciano Gualberto, 158 Travessa 3 |
| CEP: 05508-900 |
| Sao Paulo Sao Paulo State Brazil |
| Voice: +55 011 818 5254 |
| Fax: +55 11 211 4574 |
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