During the Spring 2008 semester at Olin College, we introduced the programming language occam-pi to under- graduates as part of their first course in robotics. Students were able to explore image processing and autonomous behavioral control in a parallel programming language on a small mobile robotics platform with just two weeks of tutorial instruction. Our experiences to date suggest that the language and tools we have developed allow the concise expression of complex robotic control systems, and enable the integration of events from the environment in a consistent and safe model for parallel control that is directly expressed in software.

When teaching concurrency, using a process-oriented language, it is often introduced through a visual representation of programs in the form of process network diagrams. These diagrams allow the design of and abstract reasoning about programs, consisting of concurrently executing communicating processes, without needing any syntactic knowledge of the eventual implementation language. Process network diagrams are usually drawn on paper or with general-purpose diagramming software, meaning the program must be implemented as syntactically correct program code before it can be run. This paper presents POPed, an introductory parallel programming tool leveraging process network diagrams as a visual language for the creation of process-oriented programs. Using only visual layout and connection of pre-created components, the user can explore process orientation without knowledge of the underlying programming language, enabling a ``processes first'' approach to parallel pro- gramming. POPed has been targeted specifically at basic robotic control, to provide a context in which introductory parallel programming can be naturally motivated.

Pipeline, Delta, and Black Hole are three simple patterns used in concurrent software design. We recently presented these and other patterns for parallelism at a nine-hour workshop for professional embedded systems developers. By grounding these patterns in the context of robotic control on the LEGO Mindstorms, we provided an engaging and enjoyable educational experience for our ``students,'' and reaffirmed that small, powerful languages have a place in education for beginners and experts alike.

The LEGO Mindstorms RCX is a widely deployed educational robotics platform. This paper presents a concurrent operating environment for the Mindstorms RCX, implemented natively using occam-pi running on the Transterpreter virtual machine. A concurrent hardware abstraction layer aids both the developer of the operating system and facilitates the provision of process-oriented interfaces to the underlying hardware for students and hobbyists interested in small robotics platforms.

Robotics is an engaging and natural application area for concurrent and parallel models of control. To explore these ideas, we have developed environments and materials to support the programming of robots to do interesting tasks in a fundamentally concurrent manner. Our most recent work involves the development of RoboDeb, a ``virtual computer'' pre-installed with the open-source Player API and Stage simulator to support classroom exploration of concurrency and robotic control using the occam-pi programming language.

We are interested in languages that provide powerful abstractions for con- currency and parallelism that execute everywhere, efficiently. Currently, the existing runtime environments for the occam-pi programming language provide either one of these features (portability) or some semblance of the other (performance). We believe that both can be achieved through the careful generation of C from occam-pi, and demonstrate that this is possible using the Transterpreter, a portable interpreter for occam-pi, as our starting point.

The Cell Broadband Engine is a hybrid processor which consists of a PowerPC core and eight vector co-processors on a single die. Its unique design poses a number of language design and implementation challenges. To begin exploring these challenges, we have ported the Transterpreter to the Cell Broadband Engine. The Transterpreter is a small, portable runtime for concurrent languages and can be used as a platform for experimenting with language concepts. This paper describes a preliminary attempt at porting the Transterpreter runtime to the Cell Broadband Engine and explores ways to program it using a concurrent language.

Brooks' subsumption architecture is a design paradigm for mobile robot control that emphasises re-use of modules, decentralisation and concurrent, communicating processes. Through the use of occam-pi the subsumption architecture can be put to use on general purpose modern robotics hardware, providing a clean and robust development approach for the creation of robot control systems.

occam-pi is a programming language based on the CSP process algebra and the pi-calculus, and has a powerful syntax for expressing concurrency. occam-pi does not however, come with interfaces to a broad range of standard libraries (such as those used for graphics or mathematics). Programmers wishing to use these must write their own wrappers using occam-pi's foreign function interface, which can be tedious and time consuming. SWIG offers automatic generation of wrappers for libraries written in C and C++, allowing access to these for the target languages supported by SWIG. This paper describes the occam-pi module for SWIG, which will allow automatic wrapper generation for occam-pi, and will ensure that occam-pi's library base can be grown in a quick and efficient manner. Access to database, graphics and hardware interfacing libraries can all be provided with relative ease when using SWIG to automate the bulk of the work.

In a world of ad-hoc networks, highly interconnected mobile devices and increasingly large supercomputer clusters, students need models of computation that help them think about dynamic and concurrent systems. Many of the tools currently available for introducing students to concurrency are difficult to use and are not intrinsically motivating. To provide an authentic, hands-on, and enjoyable introduction to concurrency, we have ported occam-pi, a language whose expressive powers are especially compelling for describing communicating dynamic reactive processes, to the LEGO Mindstorms.

This paper reports on the Transterpreter: a virtual machine for executing the Transputer instruction set. This interpreter is a small, portable, efficient and extensible run-time. It is intended to be easily ported to handheld computers, mobile phones, and other embedded contexts. In striving for this level of portability, occam programs compiled to Transputer byte-code can currently be run on desktop computers, handhelds, and even the LEGO Mindstorms robotics kit.

Operating-systems are the core software component of many modern computer systems, ranging from small specialised embedded systems through to large distributed operating-systems. This paper presents RMoX: a highly concurrent CSP-based operating-system written in occam. The motivation for this stems from the overwhelming need for reliable, secure and scalable operating-systems. The majority of operating-systems are written in C, a language that easily offers the level of flexibility required (for example, interfacing with assembly routines). C compilers, however, provide little or no mechanism to guard against race-hazard and aliasing errors, that can lead to catastrophic run-time failure (as well as to more subtle errors, such as security loop-holes). The RMoX operating-system presents a novel approach to operating-system design (although this is not the first CSP-based operating-system). Concurrency is utilised at all levels, resulting in a system design that is well defined, easily understood and scalable. The implementation, using the KRoC extended occam, provides guarantees of freedom from race-hazard and aliasing errors, and makes extensive use of the recently added support for dynamic process creation and channel mobility. Whilst targeted at mainstream computing, the ideas and methods presented are equally applicable for small-scale embedded systems --- where advantage can be made of the lightweight nature of RMoX (providing fast interrupt responses, for example).