Two of the biggest hard-disk drive makers, Seagate Technology and Hitachi Global Storage Technology, both said Thursday that they plan to have drives on the market with the first half of this year that are capable of holding a terabyte (1000G bytes) of data.Hitachi said it would have a drive available in the retail market before the end of March for $399. Models for use in digital video recorders and enterprise computer servers will follow in the second quarter when production volumes increase, said Doug Pickford, Hitachi\u2019s director of market and product strategy.The 7K1000 drive, which will be on show at next week\u2019s Consumer Electronics Show in Las Vegas, will have five 3.5-inch disk platters on which to store data. It will carry a SATA (Serial Advanced Technology Attachment) interface on the retail version. A model with the older PATA (Parallel Advanced Technology Attachment) interface will follow later, said Pickford. It will have a rotational speed of 7,200 rpm.Seagate said in a statement that it plans to begin shipping a 1T-byte drive sometime during the first half of 2007 to major customers like system and PC vendors during that time-frame. It didn\u2019t provide any other details of the drive or its cost. Seagate also didn\u2019t address the retail market in its statement.Terabyte drives, for long a goal of the storage industry, started to get within reach in the last year as drive makers began using a new technology called perpendicular recording.Like the longitudinal recording that has been used until recently, perpendicular recording relies on magnetically charged particles for data storage. In longitudinal drives, the north and south poles of the magnetic particles run parallel to the disk, but in the new method they are arranged perpendicular to the disk. The result of this new arrangement is that each particle occupies a smaller area of the disk\u2019s surface and so more particles can be crammed onto the disk.The new Hitachi drive will cram 148G bits of data into each square inch of disk space. In comparison, the company\u2019s current highest-capacity 3.5-inch drive, a 500G-byte model based on longitudinal recording, can only manage half that density.-Martyn Williams, IDG News Service (Tokyo Bureau)Related Links:\n\nDisk Producers Team to Push Flash-Embedded DrivesCheck out our CIO News Alerts and Tech Informer pages for more updated news coverage.