

Show HN: Adopt-a-cloud.com - deutronium

I created this site based on an idea I found at the Halfbakery (http://www.halfbakery.com/idea/Adoptacloud_2eorg).<p>It makes use of the Play framework for the web app itself.<p>The actual cloud detection is performed using Mathematica, which i've just started using 
and am really enjoying.  Originally I did the cloud detection using blob detection, as detailed in the 
blog post on the site, but I've since found a more effective solution in Mathematica.<p>Originally I did the cloud detection on the webserver itself, but found the server didn't have 
enough memory (512M) as I kept getting processes being killed by the out-of-memory killer.<p>It uses JPA (Java Persistence API) to handle 
the database - this allows the creation of records and relations based on Java objects.  
Which made creating the database really easy.<p>While using the framework I came across some interesting problems:<p>I found the Java VM would sporadically terminate due to a bug with the Java VM, this 
was alleviated by using '-XX:CompileCommand=exclude,jregex/Pretokenizer,next'.<p>I also found I would get a 'too many files open' exception, to fix this 
I used 'ulimit -n 65535' to increase the number of file handles allowed (admitedly this seems 
somewhat 'hacky' but it did the trick).<p>In order to add new clouds to my system, I make use of a script which uses curl, to upload both 
an image and a file containing coordinates.  I found I kept getting a '417 Expectation failed' error, this was apparently
happening as curl sends an Expect header which lighttpd 1.4x doesn't understand. In order to fix this
I used 'curl -H Expect:', which lighttpd 1.4x permits.
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deutronium
Clickable link: <http://www.adopt-a-cloud.com>

