MojoKid writes "Promise Technology recently launched the first Thunderbolt-compatible devices; the company's Pegasus RAID R4 and R6 storage solutions can now be ordered from the Apple Store. There's a catch, however. In order to use either storage array, one must first purchase a cable directly from Apple. The company has priced the two-meter cable at $50. As it turns out, Thunderbolt uses what's called an active cable. Inside the cable there's a pair of Gunnum GN2033 transceivers. The GN2033 is a tiny, low power transceiver chip designed to be placed inside the connectors at either end of a Thunderbolt cable, enabling dual bidirectional 10Gb/s concurrent links over narrow-gauge copper wires. The cable's $50 price may be justified, but it's also a further reminder of why Thunderbolt may follow FireWire's path into obsolescence. Apple is the only company currently selling Thunderbolt cables."