[Oz] Mozart 1.0 released: platform for distributed and constraint programming

[Christian Schulte]

[Sorry for multiple copies]

Available at http://www.mozart-oz.org

Systems supported: Many Unix-based platforms, Windows 95/98/NT

The Mozart consortium (DFKI & UdS & SFB 378, SICS, UCL) is pleased to
announce the release of Mozart 1.0, a major development platform for
open fault-tolerant distributed applications, constraint programming
applications, and logic programming applications.  The platform
implements the Oz language and is the fruit of a decade of research.
The platform is released with a very liberal license (BSD style) that
allows both commercial and non-commercial use.  Full source code is
available.  The platform includes a full-fledged interactive
development environment with many libraries and tools.  There is
extensive documentation including tutorials covering all below
mentioned application areas, a complete set of reference manuals, and
many demos.  The distribution, constraint, and logic programming
abilities are the subject of ongoing research.

Mozart provides state-of-the-art support for distributed programming
that separates the issues of application functionality, distribution
structure, fault tolerance, and open computing.  The implementation is
fully network-transparent, i.e., an application obeys exactly the same
semantics independent of its distribution structure, which is
specified separately from the application functionality. The platform
reflects distribution and fault tolerance in the language, providing
abstractions that allow full control over these issues from within
the language.   

Mozart provides state-of-the-art support for constraint programming
and logic programming.  There are four constraint systems, namely
rational trees (as in modern Prologs), finite domains, finite sets of
integers, and record constraints.  The platform is robust and able to
handle big problems.  Its performance is competitive with commercial
solutions (including ILOG Solver, CHIP, SICStus Prolog, and Prolog IV),
but it is much more expressive and flexible, providing first-class
computation spaces, programmable search strategies, a GUI for the
interactive exploration of search trees, parallel search engines
that exploit networked computers, and a programming interface to add
new, efficient constraint systems.

Distribution and constraint programming form a unique combination for
emerging application areas.  Intelligent multi-agent systems profit
from having both aspects together.  Furthermore, Mozart provides an
easy-to-use parallel search engine for constraint programming and
logic programming.  This makes it easy for ordinary users to vastly
increase the performance of compute-intensive applications, without
having to rewrite them.  

The Mozart consortium has developed significant applications with the
platform.  Here we give a brief overview; a more complete list is at
http://www.mozart-oz.org/archive.cgi.  DFKI has developed a
real-time bus scheduler, an intelligent manufacturing systems planner,
a configuration tool, and an automatic music composition tool.  DFKI
uses Mozart as the base platform for its multi-agent research.  UdS
has developed a corpus browser.  UCL has developed TransDraw, a
state-of-the-art collaborative graphic editor that has high performance
even over very slow networks.  SICS has developed applications in train
scheduling and radar configuration, and MIM (Mozart Instant Messager),
an extended version of ICQ.  

The Mozart platform includes an interactive programming interface based
on Emacs (both GNU Emacs and XEmacs are supported), an incremental
compiler, development tools (including browser, interactive constraint
visualizer, parser-generator, profiler, and debugger), an Internet-wide
module system with dynamic linking, full Web support (applets,
servlets, CGI), persistent data structures, an object-oriented graphics
interface based on Tcl/Tk, powerful interoperability features including
support for sockets and a C++ interface for dynamically-linked
libraries, a distributed garbage collector, infinite precision
arithmetic, and support for stand-alone applications.  Furthermore,
there are extensive libraries of constraints (including support for
scheduling) and search engines including parallel engines.  Performance
is competitive with commercial Prolog and Lisp systems and is better
than emulated Java.

It is interesting to compare Mozart with JDK 1.2, the current Java
release.  Mozart distinguishes itself from Java in six ways.  First,
Mozart provides true network transparency--not a single line of code
has to be changed when changing the distribution structure of an
application.  Second, Mozart provides a truly neutral network layer--it
does not make any irrevocable decisions when there are temporary or
permanent faults with processes or with the network.  Third, Mozart is
fully extensible at run-time--one can for example upgrade the interface
of a remote object interactively while the object is running and
clients are communicating with it.  Fourth, Mozart provides
sophisticated constraint programming and logic programming abilities
and tools.  Fifth, Oz is a data-flow language, i.e., computations
are driven by availability of data.  Finally, Mozart provides a much
more efficient implementation of concurrency--it is literally possible
to create millions of threads within a process.



------------------------------------------------------------------------
Christian Schulte, Programming Systems Lab, DFKI GmbH
Postfach 15 11 50, 66041 Saarbrücken, Germany
Tel: +49 681 302-5340; Fax: +49 681 302-5615 Net: schulte at dfki.de  
URL: http://www.ps.uni-sb.de/~schulte/

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