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Audio-video drives are back on the menu, with Western Digital bringing out a range of IDE and SATA hard disks that goes to a chunky 500GB – enough for up to 30 hours of HD video, reckons WD.

The drives include a number of tweaks and new technologies to optimise them for AV applications. WD claimed that they can deliver smooth playback of as many as 12 high-definition video streams at once, or for CCTV use they can record up to 16 standard-definition streams simultaneously.

AV-optimised drives first appeared a decade ago, but many of those tweaks – such as automatic self-recalibration – went mainstream, allowing standard drives to take over in most AV applications. The arrival of digital and personal video recorders (DVR/PVR) and HDTV has stretched standard hard disk technology though, as well as forcing the development of quieter, more reliable drives.

"These are not for desktop PCs," said WD technician Alexander Patterson. "They are for DVR, PVR, set-top boxes and low-end security systems."

They include a a new technology called IntelliSeek which synchs head movement to disk spin, so the head arrives at the right moment to read the data it wants as it passes underneath. This does make them slightly slower on average seek time – 12 or 13ms versus 8 or 9ms for a PC drive – but Patterson said that by taking out "hasty movement", it can cut both power consumption and noise.

"It's not a case of less performance, it is other features for different applications – it's less performance for some apps, but more performance in others," he added, noting that the AV-specific features conform to ATA standards and are not proprietary.

These are also the first 3.5 inch WD drives to include features that are now common in drives for mobile PCs, such as ramp-load, which reduces wear and increases shock tolerance by parking the read/write heads off the disk surface during spin-up, spin-down and when the drive is not operating.

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