K
nown variously as real-time, multi-tasking, multi-threaded, cooperative,
distributed, or (more recently) web enabled, systems built from cooperating
collections of independent entities have always been and will probably remain hard to
design and deliver. At the heart of this difficulty lies the definition and control of inter-
process communication and synchronization and the lack of a formalism that
addresses these issues. Most methodologies and their supporting tool sets address
how a system is built and provide solutions for requirements capture, system
specification, and software design. There are few tools, however, that deal explicitly
with deployment, ie. how a system is expected to run, and bring the same level of
discipline to it that has become commonplace in other areas.
Synchronization and inter-process communication is almost always part of any system
whether or not it is explicitly apparent in the design. The reason for this is simple;
real world problems exhibit parallelism and so software solutions tend to reflect this
fact. MASCOT (Modular Approach to Software Construction, Operation, and Test)
explicitly addresses these aspects of system design and provides a simple, elegant,
and powerful way to reason about them. MASCOT is not a replacement for modern
design techniques and tools but rather complements them by adding another
dimension to the design process. By encouraging designers to define runtime
behavior early the design rather than late in the integration phase, MASCOT offers a
unique approach to system design and development.
MASCOT was developed at the Royal Signals and Radar Establishment (now QinetiQ)
in Malvern, England, and applied as a software standard by the British Ministry of
Defense during the 1970s and 80s. MASCOT 2002 extends and enhances the original
MASCOT 2 standard to reflect advances in software and system technology since then.
MASCOT defines three main components and a unique design process that neatly
bridges the discontinuity between design and integration and deployment. MASCOT’s