how many partitions are needed?

[turbine]

Looking ahead to doing hdd install of knoppix and was wondering if I can get away with just 2 partitions, a swap partition and another partition for everything else? I never understood why all of those different partitions were needed for linux installs. Is it just for performance? The reason I want just 2 partitions is that then I can easily create a backup partition of the main partition using something like partition commander. Then if and when I screw up the os, it can easily be restored from the backup. This worked well in my experimenting with windows os's, can't see why it wouldn't for linux.

[tjcw]

1 partition is fine;you only need 'swap' if you are a bit short of real memory, and even then you might want to consider buying more real memory first.
More partitions are useful if
1) You have an old BIOS which won't boot from beyond a certain distance from the start of a disk, and you need to force the kernel below this line
2) You might want to wipe and reinstall on a partition, while leaving data on other partitions intact
3) You want to explore which of JFS, ReiserFS, and XFS suits you best
4) You want to arrange that a runaway program writing to one partition does not fill up disk which another user might need
5) You want to be able to boot several flavours of Linux and/or Windows
6) You might want to move part of your data to a different disk another day

and probably a few other reasons I have not thought of. Starting with 1 (not taking up the whole disk) and thinking about others later is quite a good idea for a personal system.

Booting Knoppix and using the 'dd' (device-to-device copy) command will work quite well for dumping and restoring partitions.

[turbine]

Thank you, tjcw, that's just the answer that I was looking for.