Author Archives: Jan Sipke

Programming the Arduino ethernet shield

The Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It features an IDE that allows you to program the Arduino using a standard USB cable. Several shields exist that extend the functionality of the … Continue reading

Posted in Hardware, Networking, programming | Tagged | 2 Comments

Model View Controller (MVC) with JSP and JSTL

In this article we will create a small web application that uses the Model View Controller (MVC) pattern with Java Server Pages (JSP) and JSP Standard Template Library (JSTL). A container like Tomcat is needed to run this combination. Thanks … Continue reading

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Changing CPU and memory settings on XenServer VMs

You can change the CPU and memory settings of XenServer virtual machines using the API. XenServer allows you to set the priority of the virtual machine CPU (called weight), set a limit on the amount of CPU the virtual machine … Continue reading

Posted in Cloud computing, programming | Tagged , | 7 Comments

Installing Sun JDK 6 on Ubuntu 10.04

The Sun JDK can be installed on Ubuntu by adding a repository and installing with apt-get. The following works with the latest versions of both at the time of writing: Sun JDK 6 update 20 Ubuntu 10.04 sudo add-apt-repository “deb … Continue reading

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Getting CPU, memory, disk and network metrics from XenServer

In a previous article we looked at getting CPU and memory metrics from XenServer. As noted in that article, as of version 5.5 of XenServer, the preferred way of getting virtual machine metrics is through HTTP calls to get RRD … Continue reading

Posted in Cloud computing, programming | Tagged , | 1 Comment

Using Google Visualization API with own data source

The Google Visualization API allows you to create charts and maps based on data you provide. This data can be in a Google Spreadsheet or be something you provide yourself. The visualizations themselves are mostly written in Javascript, although there … Continue reading

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Creating web charts using Open Flash Chart

Open Flash Chart gives you the possibility to have Flash based charts on your website without the need to know Flash. All it takes is a JSON file that describes the chart. This JSON file can be a static file … Continue reading

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