System memory vs disk usage -- why is my hard drive almost full if my system memory is half empty?
I have a white Macbook, 2.4 Ghz Intel Core 2 Duo processor with 2 GB of memory, Mac OS X, version 10.5.8, purchased in 2008. My Mac keeps warning me that my startup disk is almost full, and indeed Activity Monitor shows that my disk usage has minimal free space (2.31 GB). However, the System Memory tab shows that half my space is free.
Does the discrepancy mean that there is lots of space left on my Mac? If not, how can I identify if some sort of error is filling up my memory? Right now, I have a lot of music and documents stored on my laptop, but nothing else, and I would like to be sure it's those two things that are filling up the space.
What is the recommended method for adding more memory to my Mac, if nothing else?
MacBook, Mac OS X (10.5.8)