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Huge Pages unter Linux für MySQL nutzen

Steffen A. Mork

Um einen möglichst hohen Performance Gewinn unter MySQL zu erzielen, sollte die Größe der Buffer Pools mindestens die Größe der Datenmenge umfassen. So funktioniert MySQL wie eine in-Memory-Datenbank. Für die Default Storage Engine InnoDB ist dafür der Parameter innodb_buffer_pool_size verantwortlich. Mit dem Tool mysqltuner kann man noch Hinweise bekommen, wie man noch weitere Parameter anpassen [...]

Graphical Views for Xtext ctd.

Jan Köhnlein

(Read my previous post for a rationale on graphical views)No matter with what graphics technology you choose to implement a diagram for your Xtext-based language, there are a few things you should know in order to connect the diagram view/editor to the rest of the infrastructure. Let us first have a look how to implement a context menu action for the Xtext editor to show the element at the current cursor position in the diagram. In Eclipse, you have to implement a handler for such an action. Xtext [...]

SRF02 ultrasonic sensor with STM32F4-Discovery

Marco Scholtyssek

The SRF02 Ultrasonic range finder is a ultrasonic distance sensor, which is a transceiver with only one membrane. That's practical, because the sensor is very small and so it is perfect for small sized hardware applications. It detects distances from 16 to 6000 cm. The Sensors needs a 5 V source, so it can be directly connected to many microcontroller. It communicates through serial interface or through i²c bus (also I2C bus called). The following article describes how to connect and use [...]

DB-Connection mit MySQL über SSL

Steffen A. Mork

MySQL lässt den verschlüsselten Zugriff mit SSL zu. Dazu sollte das passende Zertifikat im Ordner /etc/ssl hinterlegt werden. Konfiguration Unter Ubuntu oder Debian empfiehlt es sich, die vom Paketverwalter mitgelieferte Datei /etc/mysql/my.cnf unangetastet zu lassen. Stattdessen können im Verzeichnis /etc/mysql/conf.d beliebig viele Dateien mit Endung .cnf ergänzt werden. Für die verschlüsselte Connection legen wir daher [...]

Graphical Views for Xtext

Jan Köhnlein

Xtext provides you with a powerful IDE and a rich featured text editor for your domain-specific language with little effort. But sometimes, a picture says more than a thousand words: You want to have some additional graphical representation of your models, a set of diagrams.Diagrams are superior to code when it comes to high-level views. But while programmers can easily cope with files that contain several hundred lines of code, the same amount of information usually blows a diagram and destroys [...]

Xbox360 controller C integration

Marco Scholtyssek

Today I have written some simple example code to integrate a Xbox360 controller into a C-based program. It reads the values of the controller axis and the buttons and displays them on the screen. The following picture shows the output of the code:In this case the buttons "A" and "TL", which is the top left button, were pressed. The project is called xboxControllerClient can be downloaded from my repository at https://code.google.com/p/scholtyssek-blogspot/. The whole configuration is in the [...]

Building Xtext Languages with Maven and Gradle

Stefan Oehme

Xtext languages should be built, tested and deployed continuously, just like any other piece of software. Users expect generators to run inside popular build tools and not just inside the IDE. In this post you will learn how to create a Maven build for your Xtext language and how to consume the resulting Maven artifacts from other projects, both Maven and Gradle.The example language that we will be building is the BuildDSL from the Seven Languages project. The language itself (i.e. the grammar and [...]

Rigol DS1052D and Open Logic Sniffer

Marco Scholtyssek

Today I have tested the logic analyzer of the Rigol DS1052D oscilloscope and I noticed that the LA does not interprete the measured signals. The Rigol DS1052D is a lower priced model, so it is ok that the data is not interpreted by the oscilloscope. But it is possible to export the signals and process them on a PC with the open source tool Open Logic Sniffer. To do so you can export them as a CSV datafile. After an easy converting the data can be read by OLS. The following step describe [...]

STM32F4 controlled omnidirectional mecanum robot with odometry

Marco Scholtyssek

In the last months I worked on a new project based on an ARM STM32F4 controller. The goal was to implement a software to control a robot with mecanum wheels (also called swedish wheels). These wheels are very special, because there are rubber rollers arranged at 45 degree on the outer rim that roll passively on the ground. Thus the robot has a further degree of freedom. This means all directions (X, Y, Θ) can be reached by the robot on a plane. Despite the lack of steering axle it has the maximum [...]

Yakindu Statechart Tools 2.3.0 is ready for Luna!

Andreas Mülder

Today, the Luna release train arrived at Yakindu Statechart Tools Station! Apart from Luna compatibility, the new release version 2.3.0 provides some great new features. If you are new to statecharts and Yakindu Statechart Tools you should take a look at our Getting Started Tutorial.Installation You can download Yakindu Statechart Tools 2.3.0 for Luna either from our dowload page or install it into your existing Eclipse installation via our update site:http://updates.yakindu.org/sct/luna/releaseNew [...]