6gbps 2TB Hard Drive from Seagate Now Shipping

Need a fast hard drive? The throughput on the new Seagate Technologies Barracuda XT hard drive is capable of transferring the contents of a CD in one second. The drive is based on the SATA3 standard, which doubles the predominantly used STA2s 3GBS throughput.

Sporting a 64mb cache, as opposed to the 16 or 32mb in most existing drives, in order to optimize burst performance, and an areal density of 368 GB per square inch, the XT must be installed in a computer having a SATA3 controller to take advantage of the increased speed. Seagate notes that the drive is fully backward compatible with legacy SATA controllers. SATA and SATA2 have throughputs of 1.5gbps and 3gbps, respectively.

The quoted speeds are theoretical ones; in actual used, due to software and hardware overheads, real-world throughput speeds are more on the order of 200mpbs. Actual transfer rates of SATA3 should be around 600mbps. The 3.5 inch, 7200 rpm drive lists for $299 and is available as of today in North America.

Designed for desktops for high-end gamers and developers of multimedia, low cost servers, and networked storage devices, it will suck up 9.23 watts of power and put out 2.9 bels of noise while seeking.Although not available yet, add-on SATA3 expansion card controllers for existing computers are coming soon.

First-generation SATA devices operated at best a little faster than parallel ATA/133 devices. Subsequently, a 3 Gbit/s signaling rate was added to the physical layer (PHY layer), effectively doubling maximum data throughput from 150 MB/s to 300 MB/s. For mechanical hard drives, SATA 3 Gbit/s transfer rate is expected to satisfy drive throughput requirements for some time, as the fastest mechanical drives barely saturate a SATA 1.5 Gbit/s link.

A SATA data cable rated for 1.5 Gbit/s will handle current mechanical drives without any loss of sustained and burst data transfer performance. However, high-performance flash drives are approaching SATA 3 Gbit/s transfer rate.

Given the importance of backward compatibility between SATA 1.5 Gbit/s controllers and SATA 3 Gbit/s devices, SATA 3 Gbit/s autonegotiation sequence is designed to fall back to SATA 1.5 Gbit/s speed when in communication with such devices. In practice, some older SATA controllers do not properly implement SATA speed negotiation.

Affected systems require the user to set the SATA 3 Gbit/s peripherals to 1.5 Gbit/s mode, generally through the use of a jumper, however some drives lack this jumper. Chipsets known to have this fault include the VIA VT8237 and VT8237R southbridges, and the VIA VT6420, VT6421A and VT6421L standalone SATA controllers. SiS's 760 and 964 chipsets also initially exhibited this problem, though it can be rectified with an updated SATA controller ROM.