I have been running low on free disk space this week. When you run Firefox 3.5, MS Word, and a couple apps on a Mac with like 1.2 GB free - and the Time Machine incremental backup starts running in the background: oh, no!

Yep, your Mac will run slower than you ever imagined. My thinking is that once Firefox runs low on memory, it is ether thrashing memory or else there is a bug in the low-memory handling. The former should work by allocating some memory to use in an emergency at the start of the program - and free it when memory is low so it can pop up a waning message that you need to exit the browser.

Unfortunately, it just hangs. I have investigted the problem and Firefox is not doing a lot when this happens, other than firing off a lot of Mach and BSD messages every half minute or so.

So, if you have a Mac or maybe any computer, and you have Firefox 3 - do not run uot of virtual memory. That is, keep at least 5 GB free at all times. I have noticed when I do that, this problem pretty much gets banished, even if I do run a couple "heavy" apps at once.

Fortunately, for me, I had some TV shows in my PVR that I had not deleted yet. Getting rid of them freed up a few dozen gigs. HDTV recorded shows use around 7 GB of storage each. Unreal.

Hope this tip helps someone who uses Firefox 3.5 and/or a Macintosh.