Joystick drivers are available for Linux. The Inventor Toolmaker book on how to extend Inventor has a section in the back on adding new hardware devices. A lengthy discussion ensues, requiring a knowledge of the details of the windowing system. I found I could bypass it by using an Inventor SoTimerSensor node set to invoke the callback function at almost any time interval with the attached node pointer. The setup for it is as follows:
SoTimerSensor *JS_Sensor = new SoTimerSensor(JS_SensorCallback, craft_xf); JS_Sensor->setInterval(0.005); //scheduled 200/sec ... JS_Sensor->schedule();
The function, called JS_SensorCallback, checks the joystick driver to see how much it has moved. This is also the place to update the flight state model to change the velocity and heading. We can check for things such as amounts of air and power left, and how deep we are, based on the current XYZ coordinates.
A few things I wish to add to this simulator are:
Networking over the Internet to join two users together
Animated objects such as fish
Direct reading of the terrain data from the Internet
More empirical parameters to ensure the craft responds the same way in the simulator as in life
Tidal and water flow effects
Light attenuation as depth increases
In addition to ease of use and availability of raw power, I like Open Inventor because whatever I develop is totally portable between my Linux machine at home and my SGI workstation at the office. Using Viewkit, Motif and Mesa, I have a tremendous amount of flexibility in choosing where and how I develop software.
Inventor and Viewkit provide the software functionality of an SGI workstation, and with the recent advances in graphics hardware, Linux PCs will be closer tomorrow to where the SGI workstations are today. Tomorrow is already planned—no one has to ask us where we want to go today.
A special thanks goes out to Alexandre Naaman for showing the way, being patient and simplifying things when they got muddled.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
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- Doing for User Space What We Did for Kernel Space
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide