[DotGNU]Bytecodes and VM's (was Something to start with)

[Torsten . Bergmann]

Norbert Bollow wrote:
>now since several different bytecode formats must be supported anyway, 
>why not also support Java bytecode, and implement that part first?

Have a look at Smalltalk implementations. Smalltalk systems run on VM's
since 1972. 
Since Java Bytecode is only a subset of Smalltalk bytecode some Smalltalk
implementations 
are able to run Java: Smalltalk/X (www.exept.de) has a Java integration as
well 
as VisualAge for Smalltalk which was used to build VA for Java and VA for
C++.

There is a free, open source Smalltalk available (called Squeak) which
actually runs on more
platforms than Java. It also runs inside of several browsers (Netscape, IE,
Opera). It is 
also possible to run it without any operating systems (Squeak NOS project).

Squeaks virtual machine is modular, written entirely in Smalltalk making it
easy to debug, 
analyze, and change. There is a Smalltalk to C translation and a VMMaker
inside of 
the system. Actually some of the original Smalltalk  creators (Alan Kay, Dan
Ingalls,
Tim Rowledge), former Sun employees and people from the INRIA institute work
on it. 
(INRIA did a lot of research on virtual machines for virtual machine and
jitters).
Alan Kay invented the term "object-oriented", he also invented GUI's, other
squeak members
worked on languages like Self (a language from Sun) and on the animorphic
VM.
That's why Squeak is very powerfull and has support for graphic, 3D graphic
(OpenGL, DirectX, own), 
Morphic, TextToSpeech system, Character Recognizer, Sound, Midi support,
Network support, ...

Maybe the Squeak VM is something to start with. It's already there -
dynamic, modular, easy
to change and completely open source.

Some pointers: www.squeak.org                           Homepage (not very
usefull)
                   http://minnow.cc.gatech.edu/squeak/  Project Swiki (very
usefull)
                   http://minnow.cc.gatech.edu/squeak/683 Some Screenshots
of Squeak                  
                   http://minnow.cc.gatech.edu/squeak/407 Squeak Virtual
Machine Hacking
                   http://209.143.91.36/super/328               Overview on
Squeak done with Squeak 

You should also have a look at the Chapter "Specification of a Virtual
Machine" from the original 
Blue Book:
http://users.ipa.net/~dwighth/smalltalk/bluebook/bluebook_imp_toc.html

Have a look at these sites or join the Squeak mailinglist. I'm sure Dotgnu
can profit from Squeak
as well as Squeak can profit from Dotgnu developers.

Cheers,
Torsten Bergmann
Phaidros Software AG

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"The main problem for the C++ community today is to use StandardC++ in the
way it was intended 
rather than as a glorified C or a poor man's Smalltalk." -- Bjarne
Stroustrup
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