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Javapolis: Day 4: Real Time Java

Posted by vbrabant on December 16, 2004 at 5:36 AM PST

During the keynote of this morning, Someone of Sun (I am sorry, but I don't remember who) speaked about Java and Real Time Application.

Java and Real Time Application ? Not possible, I though. You can't garantee Real Time when you use applications based upon JVM having a Garbage Collector that can suspend your thread at any moment, and for somes time (it may be short, but always too long for Real Time Application).

But, aside the guy, everyone could see a strange machine. Because I have'nt find a photo of that machine, let me try to describe it.

On the table, we could see 2 pc (Sun Solaris machines, and between those two pc, you had I/O Cards.
Each one of those PC were linked to those I/O Cards. Those I/O Cards were connected to something that could move along a rail. That think was in fact a pendule.

But a really strange pendule, because in place of go down, the pendule was up. In fact, the Java application always looked at the angle of the pendule and, when necesary, move the machine left or right along the rail to do some correction and be sure that pendule is always vertical, but in up position. That's the reason why someone called his demo the viagra demo.

When the guy pushed the stick, automatically, the machine moved along the rail to correct the angle, and let the stick well vertically.

He explained that only one PC was controlling the machine. And started the second machine as Backup. When backup machine was launched, he stopped the application that was running on the first machine. And the stick were always well vertically. The second PC take the relay.

Then, he restarts the application on the first PC. At that moment, that application become the backup. And he unplug the cable of the second PC, that was at that moment the master controller of the I/O Card. And the stick continues to be vertically.

Also, I forget to say that other applications were running in the same Virtual Machine on each one of those two PC. And those applications somethimes freezed due to the carbage collector.

I hope that I someone will post a photo somewhere on the web, and that I will be able to add a link here.

And the java application continues to keep the stick vertically during all the time of the next keynote. So, if people are not yet convinced that RT Application can run under the JVM, personally, I am now convinced.

Want to share your experience with RT Java Application ?

Update: Someone take a photo of the machine and publish it on Javapolis. Look at the
picture

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