Recently I downloaded the Knoppix iso over a few days using ncftp.
Quite straightforward. Had a slight problem because the iso I had was corrupted in parts and failed the md5sum test.
Next step was to correct it using rsync. It took me a while to learn to use it but once I was there I corrected the iso in about 3 minutes.
Knoppix rocks!
ftp rocks
rsync rocks.
and so does Linux
Downloading on a dialup
