You may recall some controversy last week regarding whether the hard drive in Apple's updated Time Capsule can really be considered "server-grade," as Apple has claimed. According to a source at Western Digital, the hard drive does indeed meet the server-grade requirements, at least as far as Apple has defined them.
The doubts about Time Capsule's robustness arose after a Time Capsule tear-down at French tech site Macbidouille revealed a Western Digital Caviar Green WD20EARS drive inside Apple's router/network storage hybrid device. You'll find the WD20EARS listed among Western Digital's standard consumer-grade hard drives, and neither a model spec sheet (PDF), nor a general brand product page(PDF) specify that this drive meets the 1 million mean time between failure rating that Apple has said qualifies a hard drive for "server-grade" status.
Understandably, Macbidouille and others accused Apple of exaggerating the reliability of its Time Capsule devices by using an off-the-shelf, consumer-grade hard drive instead of a more reliable enterprise model. Due to Apple's policy of rarely commenting on third-party components, it has not issued a comment to clarify the issue. Fortunately, a source inside Western Digital was willing to explain matters.
"If you enter in the drive number on NewEgg you're going to see it come up as a desktop drive. That platform is actually built on a lot of other products for a lot of different OEMs. And the specs could change depending on whatever program we're building for. Needless to say Apple has very stringent requirements that are very specific to them and very unique to them, and that drive has actually been developed and is unique for that Apple product."
When we asked whether the variation of the WD20EARS drive is rated for a 1-million-hour MTBF, our source confirmed that it was: "We don't spec our desktop drives with MTBF because our customers don't purchase in that manner, but this particular drive for this particular OEM with these unique requirements does meet those specifications."
Western Digital certainly wouldn't be the first component manufacturer to design specific versions of existing products for an OEM. Also keep in mind that MTBF is a loosely defined standard, and a 2007 study from Carnegie Mellon found vendors' self-generated MTBF ratings don't always reflect reality. Even if the numbers are fuzzy, according to Western Digital, the hard drive in Apple's Time Capsule meets Apple's definition of a server-grade product.