The ARINC 653 specification, defined for aeronautical applications, has the goal of providing a standard interface between a given real-time operating system (RTOS) and the corresponding applications. It also provides robust partitioning, with the final goal of guaranteeing safety and timeliness in mission-critical systems. The interest in ARINC 653 has extended to the aerospace industry, which resulted in the definition of an architecture, compliant with the specification, allowing for operating system heterogeneity. In this paper, we introduce the problem of integrating generic operating systems onto this architecture, and explore the case of GNU/Linux. Adding GNU/Linux allows running existing applications or interpreted scripts without needing to port the application or interpreter to an RTOS. In embedded systems, we have to cope with scarce resources and diverse existent hardware, and a balance between both issues must be reached. For such, we show the genesis of such a solution.

Real-time systems usually consist of a set of periodic and sporadic tasks. Periodic tasks can be divided into two classes: synchronous and asynchronous. The first type does not define the task first release, contrary to the second. Hence, synchronous periodic tasks are assumed to be released at the worst instant: the critical instant. The schedulability test is reduced to check a single execution of the task under analysis. The integration of sporadic tasks is also straightforward: they are treated as a periodic task with maximum arrival frequency. On the other hand, asynchronous periodic tasks require a test for each release in the hyper period and the integration of sporadic tasks is not trivial: the worst release instant is unknown a priori. However, they do not assume that the tasks are released at the worst instant.This paper presents a new schedulability analysis method based on the Response Time Analysis (RTA) to determine the worst response time of both asynchronous periodic and sporadic tasks, scheduled by a fixed-priority preemptive algorithm with general deadlines. It also presents another method that enables the introduction of a user configurable degree of pessimism, reducing the hyper period dependency.

This paper presents VITRAL, a multicolor text mode window manager designed for embedded real-time systems. Therefore, timeliness requirements and resource constraints are the main concern. Even though complex graphical environments are not supported, the application can use VITRAL to build a powerful, dependable environment that reports the system state and still provide a friendly interface to the user.

The CAN Enhanced Layer (CANELy) is a CAN-based infrastructure capable of extremely reliable communication. This paper describes the mechanisms and the techniques used in CANELy to enforce system correctness in the time-domain despite the occurrence of network errors (inaccessibility). The paper discusses how to integrate in the existing CANELy machinery, the control of inaccessibility and the management of timers, at several levels of the system. In particular, application and low-level protocol layers are addressed. In addition, a relevant set of parameters are available for system monitoring, allowing the validation/enforcement of the system model.

In a quasi-synchronous environment worst-case times associated with a given activity are usually much higher than the average time needed for that activity. Using always those worst-case times can make a system useless. However not using them may lend to timing failures. On the other hand, fully synchronous behavior is usually restricted to small parts of the global system. In a previously defined architecture we use this small synchronous part to control and validate the other parts of the system. In this paper we present a light-weight group protocol that together with the previously defined architecture makes it possible to efficiently handle timing failures in a quasi-synchronous system. This is specially interesting when active replication is used. It provides application support for a fail-safe behavior or controlled (timely and safe) switching between different qualities of service.