I made some research and found out that Deep freeze is not available for ubuntu. Is there a software like deep freeze for Ubuntu 10.04. To prevent writing data on the disk. I need this so that I could try all sorts of stuff on Ubuntu without worrying if I could damage the Windows installation that is installed along side with it. Virtual box is good. But the performance is not. Because I only have 2gb of ram.
If you just want to prevent damage to the windows partition you could just unmount it.
If you want to be able to snapshot the ubuntu (or windows) partition the dd command can do that with little fuss.
CAUTION: The dd command should only be run against unmounted partitions. You can run it from the ubuntu CD if you need the ubuntu partition unmounted.
The closest thing to Deep Freeze for linux would be to create a UnionFS of your actual file system and a tempfs in memory or on a spare partition (memory is limited, but wipes on reboot; spare partition can hold a lot more changes, but must be manually wiped on shutdown/bootup).
If you're worried about accidentally writing to your windows partition, then you should unmount it completely. If you do this, there is very little you could do to your ubuntu partition that would effect it (namely, playing with partition editors or messing up GRUB could still affect it; nothing short of backups can help against partition editors, though the UnionFS approach can prevent against accidentally messing up your boot files.).