A specification that eliminates the need for SATA (Serial Advanced Technology Attachment) drives to use a separate power connection should be available to disk drive makers by the end of 2008, according to the Serial ATA International Organization.

The SATA standards group this week disclosed that work is well under way on the specification, called Power Over eSATA. The development of the spec is being overseen by the organisation's Cable and Connector group and should be ready by the second half of this year. Knut Grimsrud, president of the organisation, predicted that products based on the specification should be available shortly thereafter.

Grimsrud said the specification would eliminate the need for SATA external hard disk drive or SATA optical disk drives to use an external power source. Instead, the drives would use a Power Over eSATA cable to gain power directly from a host system, he said. The result: End users could more easily expand storage capacity and access stored laptop and desktop data because wall-plug outlets would not be required, he said.

"[Power] availability of devices is becoming an issue. When you want to hook up to an external storage device, it has to be powered separately,' said Grimsrud. The specification is designed "to improve convenience for adding another device to your system, on-the-go casual storage expansion and quick backup from laptop scenarios."

Grimsrud said vendors can use the specification to provide power to a single external hard disk or optical disk drive. The new cable will enable support of most existing external SATA connectors and provide a 3Gbit/s interface transfer rate, he said.

The Power Over eSATA specification was jointly created by Intel, Hitachi and other disk drive makers, along with cable assembly and laptop manufacturers, remarked Grimsrud. He predicted that once the specification is finalised, systems manufacturers will allow external storage devices to use either an Power Over eSATA cable or traditional external power adapters. Grimsrud added that over time, the latter should be phased out.