Odiug replied to the topic 'A better FITS viewer?' in the forum. 4 years ago

Astroberry uses swapping to a compressing RAM disk (maybe the default for Ubuntu Mate). That might be helpful when unused program parts are put away in a compressed form to provide more memory for active programs. But I think it is not a good idea when memory is already scarce.

I am using a swapfile now with swappiness set to 0 (only swap when absolutely necessary). On zooming in FITS Viewer the Pi did become very slow, as expected due to swapping to sd-card, but KStars FITS Viewer did not crash yet.

What you have to do:
$ sudo apt install dphys-swapfile

You can configure it in /etc/dphys-swapfile, but default settings seem to be OK. It will use a 2GB swapfile (Maybe too big. I guess the Pi will become unusable before this is fully used)
Set swappiness to 0 by adding "vm.swappiness = 0" to the end of /etc/sysctl.conf.

Regards
Guido

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