This article is from the FAQ, by with numerous contributions by others.
The basic libraries define various patterns for dealing with
concurrency, synchronization, and communication. These patterns are:
system, semaphore, fork, monitor, port, restrictedPort, objectPort,
qualifiedPort, conc, and alt.
Graphical User Interface framework
The Mjolner System contains from release 4.0 a platform independent
framework for the construction of graphical user interfaces, called
X Window System framework
The Mjolner BETA object-oriented interface to the X Toolkit Intrinsics
(Xt) is called XtEnv. This pattern contains the basic patterns common
for many user-interface toolkits built upon the X Window System, but it
does not contain any higher-level user interface elements. It is
typically used together with a widget set containing such user
interface elements built on top of it. Examples of such widget sets are
the Athena Widgets, OPEN LOOK, and Motif. The Mjolner System currently
includes object-oriented interfaces to the Athena Widgets (AwEnv) and
to Motif (MotifEnv).
Bifrost graphics framework
The interactive object-oriented graphics system Bifrost is based on the
Stencil & Paint imaging model. Bifrost models computer graphics images
by abstracting the geometric and color properties of graphical objects.
The important new concept introduced in Bifrost is that there is one
basic drawing primitive, the graphical object. The graphical object
unites interaction, graphics modelling, and graphics context. Bifrost
includes extensive support for various kinds of interaction:
interactive creation, reshaping, translation, scaling, and rotation of
graphical objects. The object-oriented approach makes extensibility and
tailorability a simple task, and facilitates object-oriented drawing
applications. One of the main goals of the development of Bifrost was
to make the graphics system independent of underlying graphics and
A distributed object system is available for enabling transparent
access to BETA objects located on different hosts on the network.
A distributed object-oriented database system for BETA objects is
currently being developed.