I'm in the market for an external hard drive and I remember someone mentioning these. It sounds like a no-brainer for me but I'm finding very little information about them. Do they even exist? Are they a good idea or should I just go with a standard ext hard drive? If I should get one, I'd really appreciate a link for one, ideally a 1 TB split into 500 GB halves, or even a 2 TB split into 1 TB halves. Thanks!