When I was installing linux that last time, I noticed something I've never noticed before, it had an option for hidden fat12, fat16, and fat32 partitions, what's this all about, what's a hidden partition? That and I didn't even know there was a fat12 partition, what's this about? If I have a hidden partition, how is this partition visible and all the data it contains, and can people in windows see it, or if you do a hex edit of the hard drive can it be seen? I need to know all the particulares of a hidden partition.

FAT12 is normally only used on floppy disks. "Hidden" FAT partitions probably refer to "hidden in dos/win", and not "hidden in linux". One of the nice thing about linux is that it hardly ever tries to hide anything from you. The whole thing sounds like a feature from ancient dos times, I've never seen it being used anywhere. Try a google search for it or something.

Some manufacturers (eg Compaq, Gateway etc) use hidden partitions to save system restore/repair stuff.

Actually, even the most recent OS from Micro$oft still hides things from you, because it's possible to have an hidden NTFS partition! If your C: partition is NTFS, try changing its type to hidden NTFS (17 in hex) and Windows won't boot anymore!!