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WD stage whispers up new AV surveillance drive

Best-in-class reliability? Hmm

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Western Digital has a new disk drive for audio-visual applications with a claimed best-in-class reliability which is far below enterprise drive reliability levels.

The target markets are surveillance camera systems, digital video recorders and other audio-visual applications.

The WD AV-25 is a 2.5-inch SATA 3Gbit/s drive with 160, 250, 320 and 500GB capacity points. It's designed for 24x7 operation and has two platters. WD says it's quiet, rated at 23bBA idle and 25dBA seek. Its mean time before failure (MTBF) is one million hours.

The drive is economic with power, drawing 0.65 watts when idle and 1.6 watts when reading or writing data.

WD says the AV-25's drive arm frequently sweeps across the disk to reduce uneven wear on the drive surface which it claims is common to audio video streaming applications.

A comparison with Hitachi GST's C5K500 surveillance drive is useful but also frustrating because some of the measurements are incomparable.

For example, HGST doesn't provide an MTBF rating for its C5K500 drive at all. Score one to WD.

By the way, an enterprise SFF drive, like Seagate's Savvio 10K.4 has a two million hour MTBF rating, double that of the AV-25, implying that A/V drives are not reliable in the enterprise sense at all.

HGST says its drive supports 600,000 load/unload cycles while WD says the AV-25 supports more than 300,000. Score one to Hitachi GST.

WD's dBA measure of sound refers to sound pressure with the number weighted for the human ear's sensitivity. HGST uses a Bel measure instead, indicating the drive's sound pressure - 2.4Bels when idle and 2.5 when seeking.

The trouble is that there is no simple conversion between dBA and Bels. Some HDD noises are more irritating than others, although both can be at the same sound pressure.

It's sometimes said that occasional head movements can be quiet but irritating, and the AD-25 drive makes these to avoid uneven wear on the platter surfaces. WD says noise levels "have been minimised to less than one sone - virtually below the threshold of human hearing". We can't find any sone measurements for the C5K500.

Basically we can't say if the AV-25 is quieter or louder than the C5K500, nor can we say if it's more or less reliable, as HGST provides no MTBF rating at all. The AV-25 certainly uses less power than the HGST drive though. It also has a 32MB cache, quadruple HGST's, and WD says it can stream 5 simultaneous HD video streams.

WD's AV-25 drive is available now at all capacity points except the 500GB one, which will be ready next month. WD's recommended street prices are $50.00 - $80.00 depending on capacity. ®

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