RTAI - Linux im harten Echtzeiteinsatz

Der Vortrag gibt eine Einführung in die Konstruktion von harten Echtzeitsystemen auf der Basis von Linux und RTAI. Inhaltliche Schwerpunkte sind: Virtualisierung der Interrupt-Hardware, Überblick über das Realtime Application Interface, Programmierung von RTAI-gestützten Applikationen, Alternativen: RTLinux, Microkernel & Co

DSPs as flexible Multimedia Accelerators

The increase of multimedia data processing requires immense processing power and transfer bandwidth as well as the consideration of real-time requirements. To reduce the CPU load the integration of flexible coprocessors seems to be a promising approach. This paper focuses on the integration of Digital Signal Processors (DSPs) as flexible multimedia accelerators into standard PC architectures running microkernel-based systems. Three components proved essential for multimedia acceleration: First, a data transfer mechanism capable of sustaining at least 30 Mbytes/s transfer rate, second, a DSP kernel with static scheduling and a very efficient context switch and third, a microkernel server running at the host which is responsible for data transfer between DSP and CPU and for calculating DSP schedules. 1. INTRODUCTION The increasing integration of multimedia data into applications requires immense processing power and transfer bandwidth as well as the consideration of real-time requiremen..

On the Integration of DSP Hardware into a Microkernel-based Operating System

Two technological developments reraise the debate about the use of DSPs as accelerators for certain applications vs. the employment of standard offthe -shelf microprocessors: ffl Tremendous development investments make general-purpose microprocessors even more powerful by the use of superscalar execution and sophisticated caching structures. ffl Microkernel-based operating system architectures permit very flexible decomposition of application systems due to their efficient message passing capabilities. Hence, this paper reports on two experiments. First, some elementary algorithms are run on a DSP and a modern superscalar microprocessor. Second, a DSP board is integrated into the message passing scheme of a modern microkernel-based operating system and a more complicated application is run on a DSP and evaluated. 1 Introduction Multimedia applications introduce at least two problems: ffl The need for high computing power and transfer bandwidth between CPU and peripheral devices. ..

Booting Linux Really Fast

Abstract This research project evaluates startup times of the linux boot process from power-on until user login. Time consuming parts of the boot process are investigated and methods how to speed up the whole process are discussed. It includes an analysis and comparison of different BIOSes, the kernel startup sequence and different approaches to start user space services. This project also compares the startup times of everyday desktop systems with the EPIA-ML6000EA Mini-ITX board, an embedded x86-compatible system

Der Raspberry Pi als Plattform für Fluoreszenzmessungen unter Echtzeitbedingungen

In diesem Beitrag wird vor dem praktischen Hintergrund einer Fluoreszenzmessung der Raspberry Pi als Plattform für ein Echtzeitsystem betrachtet. Es werden dabei Linux und Xenomai im Kernel- und Userspace hinsichtlich der äquidistanten Ausgabe eines Impulses am GPIO-Ausgang verglichen. Für einen Xenomai-Kernelprozess werden die Reaktionszeiten der Flankenerkennung mittels Polling und Interruptsteuerung untersucht. Das Serial Peripheral Interface wird bezüglich seiner Einsetzbarkeit zur Datenübertragung unter Echtzeitbedingungen betrachtet und die Ausführungszeit einer 2 Byte-Übertragung vermessen. Aus diesen Untersuchungen wird die maximal garantierbare Abtastrate für die Fluoreszenzmessung hergeleitet