Overall assessment

I'm not sure what to make of Red Hat's strategy in releasing the Embedded Linux Developer Suite at this time. It has an unfinished feel, obvious to even the most casual user. The user interface reminds me of some quick-and-dirty GUIs I've written myself to meet temporary internal needs, rather than a professional user interface intended for customers. (more…)

Building target images for three SBCs

Despite the GUI and documentation provided with ELDS, I did manage to configure and build kernels and root filesystems for the three single-board computers I'm using as test platforms for this series of reviews. The SBCs — an Ampro Little Board/P5x, a… (more…)

Configuring the system

Having set up the project, we then move to configuring the system. To do so you run the main program of the ELDS user interface, improbably named “pconf3.py”. This program could serve as a textbook case on how not to design user interfaces. (more…)

The purpose of benchmarking systems is most commonly to alow judgment if a system configuration is suitable for a given RT-spec. Aside from the fact that these RT-specs are most often quite vague, the problem of benchmarking is not well resolved in the currently available hard real-time solutions for Linux. (more…)

We present a methodology to perform fine-grained cycle-accurate timing measurements crossing the user-kernel boundary. Special attention is payed not to deteriorate the results by the measurement process itself. Next, we apply our methodology to obtain execution timing for the system entry and exit paths on x86-based Linux systems. (more…)

A real-time virtual resource is an abstraction for resource sharing where the application task groups sharing a resource must meet timing constraints in the absence of knowledge of all the timing requirements of all the task groups, thus prohibiting a global schedulability analysis. (more…)

POSIX is a set of international standards whose main goal is to support applications portability at the source code level. It defines an operating system interface and environment based on the UNIX operating system. A series of POSIX Real-Time standards have been defined to support real-time applications portability. (more…)

In October, 2004 the authors of this paper announced a Real-Time Linux Kernel prototype on the Linux Kernel mailing list. The Real-Time Linux prototype introduced preemptible locking into the Linux kernel, and allowed task preemption to occur while tasks were executing within critical sections, resulting in a dramatic improvement in the Real-Time response of the Linux kernel. (more…)

As real-time capabilities are becoming relevant in main-stream desk-top Linux more and more, and new variants and ideas are popping up all over the Open-Source world, a notoriously incomplete, overview of the existing variants of soft-real time Linux is given in the article. Many of the variants are for special purposes, some are more general approaches that target every-day soft-rt demands, like… (more…)

WSN (Wireless Sensor Networks) are considered the sensing technology of the future. Many experimental systems have been designed to create a WSN to collect environment data and accessed via a web-interface. But almost WSN are build on the special technology including the software and hardware. (more…)

This paper investigates the possibility of using standard, low-cost, widely used FireWire as a new generation fieldbus medium for real-time distributed control applications. A real-time software subsystem, RT-FireWire was designed that can, in combination with Linux-based real-time operating system, provide hard real-time communication over FireWire. (more…)

The Real-Time Driver Model (RTDM) is an approach to unify the interfaces for developing device drivers and associated applications under real-time Linux. The device models supported by RTDM will be introduced in this paper. An overview of the low and high level APIs will be given and the concept of device profiles for defining generic device interfaces will be presented. (more…)

As part of a Cambridge-Massachusetts Institute funded project a set of teaching resources is being developed around the ARM based Balloon Board microcomputer. The system is being designed to give students and academics a preinstalled system with support material and low cost hardware for control and data acquisition projects. (more…)

Real-time embedded systems used to be hand tailored to fit requirements and constraints of applications. But the increasing complexity of applications and the rapid evolution of hardware make these practices unbearable to face nowadays industrial reality with very fast evolution of requirements. (more…)

The `C-API Simulink Target for RT-Linux' (CAPI_STRTL) is an application developed to extend the functionality of the original `Simulink target for RT-Linux' (STRTL) by providing the user with full parameter tuning and signal access, of a real time application running in a RT-Linux kernel, independent of the Simulink/MATLAB interface. (more…)