Java and legacy operating systems, graphics drivers, &c.
So I had to jump into the same operating system the client uses to verify some code changes still worked - really just a formality as I have jjmpeg working fine there and I was only changing some Java code.
Pretty weird results though. First I had some unpleasant flashing when the code was painting a bitmap - I thought it might've been from the latest jre update together with my habit of poking BufferedImage array's directly, but I checked and this code doesn't do any of that. All it does is replace the bitmap pointer and request and invalidate the component. Annoying but no show stopper.
But then the whole system crashed, ... graphics driver? Who knows. Probably. The AMD drivers are known to be ... problematic.
I rebooted, updated the AMD driver and rebooted again and in the short period of verification which followed I didn't see it happen again.
Except then I noticed something else - part of the application runs slower. Based on user input I do a bunch of deconvolutions on frequency-domain data, convert it back to spatial and merge the results to an image. It runs in another thread and on GNU/Linux it pretty much keeps up with as fast as the sliders move. Under the other system I noticed it was a bit laggy - nothing great but noticeable. The result of all this goes to a view which one can zoom using the scroll-wheel. Doesn't make any difference to the performance on GNU/Linux - it's just scaled during the paint() call, but it drops to a crawl on that other system if one zooms in a few times ... like down to 2-3 fps or something shocking.
As I was there I also tried the slideshow thing I wrote for JavaFX too. Apart from not traversing directories as I thought I was (bug), it was definitely slower there as well. Noticeable lags just as it started to transition in the next image. Possibly from GC, or from the blur effect.
I previously noticed other weirdness when I was playing with Glassfish based application a few months ago (in hindsight I should've just used the embedded webserver in SE, but i digress). I had few troubles getting it going on my system - just installed into ${HOME} and pointed netbeans at it - and just let it manage it. But all sorts of issues on the other system. In the end I had to use the command line tools to get anything to work (it was being used for development and running it, so having netbeans function would have been beneficial), and a few other bits of system pokery jiggery I shouldn't have needed.
Maybe it's just a Java thing, but shit just doesn't seem to work too well on that legacy system ... and that's before you count the unusual disk activity and long pauses opening applications.