I have 2 internal harddrives (500 and 750 gb) that I want to join up into 1 logical drive and use on different computers. How can I do this? Raid? Which one? if I move the harddrives to another computer (win7 to xp and back. Im using a hdd case with multiple bays), will it be maintained? I will be connecting the harddrives with sata to USB cables, not normal sata cables
There is only one way I know to do that, and it would be with a removable hardware RAID card (or possibly if you could replicate the software RAID settings, but this is doubtful imo). Because the data necessary to form the RAID volume is stored on the card, it can be made portable from system to system.
All that said, I cannot discourage you enough from doing this. You would have to open your system, more the card and the drives, which is a hassle, and increases your chances of hardware failures every time you move it.
Above all, experience makes me really suspect that something could go wrong and put your data at risk. A better option is to just buy an external HDD with 2TB on it. It is cheaper than the RAID card, easier to move from system to system, and your data is probably safer.