The goal of a real-time operating system (RTOS) is to support real-time and embedded system (RT/ES) application development, which differ from general-purpose applications because of the size, weight, and power (SWaP) and timing constraints imposed by embedded applications. Useful RTOS features include real-time thread scheduling, thread communication, synchronization, interrupt handling, memory management, file systems, device drivers, networking, and debugging support. The Real-Time Executive for Multiprocessor Systems (RTEMS) is a free and open-source RTOS that supports over a dozen processor architecture families and over 150 embedded system boards. RTEMS is designed to support embedded applications with stringent real-time requirements while being compatible with open standards such as POSIX. RTEMS includes optional services such as TCP/IP networking and file systems while still offering minimum executable sizes under 20 KB in useful configurations.One of the primary functions of an RTOS is to select threads that can obtain access to resources such as shared memory and processor time. RTEMS uses multiple algorithms to manage both waiting threads and those ready to execute. The thread execution schedulers include the traditional RTOS round robin and deterministic priority schedulers, rate monotonic, earliest deadline first (EDF), constant bandwidth server (CBS), and simple SMP scheduling algorithms. The RTEMS scheduling framework allows the application developer to select the thread scheduling algorithm that best meets the application's space and time requirements. ÂȃWe will present how this framework can be used by researchers to integrate their own scheduling algorithm into RTEMS and test it using a scheduling simulator before deploying it on target hardware.

In this paper, we describe the design and development of a network of large unmanned ground vehicles (LUGVs) using lowcost, off-the-shelf technology and building upon experience gained at the 2005 Defense Advanced Research Projects Agency (DARPA) Grand Challenge. Our unique distributed architecture allows robots with different capabilities to interact, facilitates the use of multiple programming languages, and supports location and employment transparency of the interacting software agents. We wrote safety-critical and real-time software in Ada to benefit from the language's precise semantics and timing control, while writing navigation, maneuvering, user interaction, and visualization software in Java for rapid, flexible development.

This paper describes a software component model that encourages reuse in application families by recognizing and leveraging similarities between products within a product family, as well as among product families themselves. By applying a product-oriented view, developers gain insight into the capabilities of the organization's products and can leverage that insight to incorporate common software components across the entire enterprise. This component model is being applied to an existing family of similar embedded systems whose application software is written in Ada. Features of this language will be examined in the context of how they facilitate construction of reusable product line-based components.

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The Open Group Future Airborne Capability Environment (FACE ™ ) Consortium has developed a reference architecture and standard for real-time embedded avionics systems. The FACE Technical Standard defines required capabilities for real-time operating systems (RTOS), portable components, and a shared data model to facilitate information exchange between components. FACE RTOS requirements are based on ARINC 653 and POSIX 1003.1b with tailoring to address the safety and security needs of avionics systems. Deos is a safety-certified RTOS that supports ARINC 653 but not POSIX. In contrast, RTEMS is an open source RTOS that supports POSIX but not ARINC 653. Integrating a paravirtualized RTEMS with Deos combines the strengths of both and provides a path to conformance with the FACE Safety Base operating system profile. This paper presents the FACE operating system profiles and discusses the technical challenges of the paravirtualization and integration effort.