Techniques allowing kernel tasks and user space processes to share large blocks of memory are presented. In particular, “mbuff/” device driver is introduced. Simple examples of synchronizing producer and consumer threads using only shared memory are given. (more…)

Comedi is a collection of drivers, common core, and high-level programming interface for data acquisition hardware, including A/D converters, D/A converters, digial I/O, and timer/counters. Comedi is somewhat unique among Linux drivers in that it equally supports real-time and non-real-time applications. (more…)

The rt_com module provides a standard serial port driver for Real-Time Linux. It defines a API to access the generic PC-architecture serial ports from Real-Time space. rt_com works with NMT RT-Linux as well as RTAI. This talk gives an outline of the programming interface as well as of the internal structure of the driver. (more…)

SimuLinuxRT is a realtime interface to the SIMULINK package that allows one to run realtime code right from the SIMULINK diagram. It runs under RTLinux developed by FSM Labs. Simply draw a Simulink diagram and click Build. Click Run — the process will run in realtime at a specified rate up to 50 kHz. (more…)

There is an ever-increasing demand from the Industry for a flexible, modular and a cost-effective CNC machine servo controller. The primary aim of this research is to develop a real-time PC-based servomotor control system. Such a machine controller is not only required to perform control functions but also do other functions like database maintenance, tool path planning and optimization, and operator… (more…)

Modern automatic control systems need 1) logically complex and computationally expensive controller algorithms and I/O; 2) real time data storage of plant information such as states, inputs, and outputs; 3) real time plotting capabilities; 4) real time controller parameter updates (both scalar parameters and matrices); and 5) real time access to reference signals; 6) remote monitoring for safety purposes. (more…)

This paper presents an architecture and design methods for rapid development of real-time control systems such as CNC or robot controllers. PICARD (Port-Interface Component Architecture for Real-time system Design) is a software architecture and environment which is aimed to reduce development time and cost of real-time control system. (more…)

Hard real-time Linux variants, RTLinux and RTAI, both use fifos and shared memory to communicate with user applications. In this work, we describe a new package, lvrtl, which allows LabVIEW VIs to use these mechanisms in a completely generic way. For the get operations, the incoming data is collected into a dynamically resized array thus handling scalar and array data for several different data types. (more…)

This paper discusses the different benchmarking tools used to evaluate the performance of Linux and their suitability for evaluating Real Time system Performance. The importance of using Statistical Methods as well as defining absolute hard limits is presented. The author will then present an Open Source Test and Evaluation Suite toolkit which rapidly allows system performance to be monitored and… (more…)

This contribution describes a possibility to build critical real-time applications using RT Linux 2.3 and LabVIEW 5.1 for Linux. Therefore a software interface has been added to LabVIEW, which gives control over real-time processes running on RT Linux. Unlike LabVIEW-RT, the real-time processes are programmed as linux kernel modules using “C” and do not need additional devices for hard real-time features,… (more…)

The “less is more” approach to Embedded Linux toolkits

Making use of the standard Linux installation and development procedures is not necessarily a bad thing, and this suggests the second general approach to Embedded Linux toolkits. The standard Linux workflow is not unusable — it just has chaotic documentation, and could use some utilities oriented toward deploying Linux in embedded… (more…)

Development Process

The development process is essentially that of Linux, with the addition of some useful utilities. (more…)

Other observations

Notably absent from BlueCat is a tool for selecting packages to be included in the target root file system. The competing toolkits all have ways to specify what components are to be included, though with varying features and usefulness. Although this would seem to be a serious deficiency, BlueCat's lack of this type of tool is mitigated somewhat by the large number of… (more…)

Articles and whitepapers about Embedded Linux and the Embedded Linux Market (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…)