Carsten Böke

Dynamic online reconfiguration for customizable and self-optimizing operating systems

When applications adapt their behavior to the requirements of the environment, their resource usage can change dramatically. The resource usage implies the services that the applications require from the operating system. Thus, the operating system must either provide all services that are totally required over time or reconfigure itself. Reconfiguration of the operating system means to support on demand services or the possibility to degrade services. We present an approach where we extend our offline customizable operating system in order to be dynamically reconfigurable during run-time. Additionally, we describe the procedure how the operating system is aware of the current required services. We claim that the resource usage between the applications and the operating system is optimized. Thus, we derive a self-optimizing real-time operating system (SO-RTOS). This work concentrates on the integration of the configurator, which models the design space and controles the low-level reconfiguration, and the resource manager, which is responsible for the timeliness and optimality. An optimization case study realized on a prototype validates our approach.

Pr/T-Net Based Seamless Design of Embedded Real-Time Systems

During the last years we have been working towards a complete design method for distributed embedded real-time systems. The main characteristic of the methodology is that within the critical phases of analysis and synthesis the system under development is available in one unique model, that of extended Pr/T-Nets. Among several other reasons we have chosen a high-level Petri Net model in order to benefit from the multitude of analysis and synthesis methods for Petri Nets. Even though the methodology is based upon one common model, it nevertheless supports the modeling of heterogeneous systems using different specification languages. The methodology was introduced and described in several former publications. In this paper we therefore only give a brief overview and afterwards go into details of our recent work, namely the transformation of proper Pr/T-Net-models into synchronous languages, the partitioning of Pr/T-Nets and an OS-integrated execution engine for Pr/T-Nets.

Customizing the configuration process of an operating system using hierarchy and clustering

Configuration is the process of composing a system from a predefined set of objects. In our approach these objects and their dependencies are described in a graph-based model. Depending upon the requirements of a given application, a configurator chooses required services from a component library by following a set of rules that govern the configurator. When a well-defined hierarchical clustering mechanism for the object graph joins the process preceding the configuration step, the advantages are manifold. The rules of clustering aid the configuration process by not only encapsulating the objects as clusters and sub-clusters but also streamlining the configuration process. The configurator chooses optimized paths by taking advantage of clustered objects, for a given set of reasonably complex requirements. Also, when a change in the set of requirements takes place, it directly attacks the cluster in question with the aid of rules instead of doing the global search for identification of the involved objects. Added advantages result from keeping the rules of clustering inline with the configuration process itself. In this case the entire process is able to support different clusters for different applications. In this paper this approach is discussed in the context of configuration based real-time operating systems.

Software IP In Embedded Systems

IP-based hardware design became an important topic during the past years. There is an even older tradition of reuse of software components. In this contribution we try to address some key problems of software reuse. First of all, in a bottom-up approach we study some underlying communication techniques used to couple different software components. As the most general solution of this problem is CORBA (Common Object Request Broker Architecture) from our point of view, this technique is discussed briefly. From the bottom we move directly to the top. The most flexible way of handling reusable software IP is to deal with their abstract model. Following this approach, modules can be embedded to various target environments using standard synthesis methods. The problem of protecting property in this approach is not discussed in this chapter. We concentrate on how to combine modules that have been modelled in various languages. At least when using a language coupling approach strict support to define bridging semantics has to be provided. A very useful means for this purpose is given by the ASM (Abstract State Machine) method, which is shortly introduced in the chapter. When software IP has to be used this IP resides on various databases in most cases. We discuss, how design workflows can be defined that allow to access such remote IPs. The exchange format XML plays an important role in this context. Finally we discuss an application example: the application-specific synthesis of real-time operating systems (RTOS) and real-time communication systems (RCOS) from a library of reusable and highly generic software modules.

Entwurf konfigurierbarer, echtzeitfähiger Kommunikationssysteme

Dipl.-Inform. Carsten Boke hat eine Ausbildung zum Kommunikationselektroniker bei der Nixdorf Computer AG abgeschlossen. Danach hat er Informatik mit Nebenfach Elektrotechnik an der UniversitätGesamthochschule Paderborn studiert. Seit 1995 ist er wissenschaftlicher Mitarbeiter in der Arbeitsgruppe von Prof. Dr. Rammig am Heinz Nixdorf Institut der Universität-GH Paderborn. Seine Forschungsinteressen liegen im Bereich von echtzeitfähigen Kommunikationssystemen für eingebettete verteilte Systeme.

Ein selbstoptimierendes Echtzeitbetriebssystem für verteilte selbstoptimierende Systeme

Selbstoptimierende mechatronische Systeme passen sich an verandernde Bedingungen zur Laufzeit an. Statische Systemsoftware fur eine solche Anwendungsklasse muss fur den allgemeinen Fall konfiguriert sein und ist dadurch nicht optimal. Deshalb wurde ein als Multiagentensystem realisiertes selbstoptimierendes RTOS entwickelt, welches sich zur Laufzeit optimal an die sich dynamisch andernden Anforderungen von selbstoptimierenden Anwendungen anpasst. Hierfur wurden Strategien auf RTOS-Ebene entwickelt, um die Dienstestruktur dynamisch an die Anforderungen der Anwendungen anzupassen. Das System muss dabei starken Echtzeit- und Sicherheitsbedingungen genugen.

PARADISE: Design Environment for Para llel & Dis tributed , E mbedded Real-Time Systems

1 IntroductionToday’s embedded systems (ES) are characterized by more and more parallelism,distribution over different locations and hard real-time (RT) requirements.Consequently, the modern, structured design process has to deal with heterogeneousrequirements and restrictions. Especially the integration of HW-design tasks with SW-design tasks and operating system functionality with respect to RT requirements is amain challenge. The integration leads to systems with enormous overall complexitybecause the complexity of each design partition itself has been doubled nearly every