I had about 8.9GB hard disk space before installing Snow Leopard (had Leopard before). After installation, the hard disk space increased to 20GB.
What caused this huge jump? I know some webpages says it is because the way Apple calculates disk space, using 1,000,000,000 instead of 2^9 for a GB, but the difference should be only 7.4%
2^9 = 1,073,741,824
So, why did 8.9GB of free space become 20GB? 8.9 x 1.074 = 9.56GB, so why is there an extra 10.5GB? Even if some printer drivers were deleted, they should only take up tens of MB, not 10GB.