Originally posted by: gwag
Originally posted by: SkyBum
Originally posted by: ribbon13
MTBF determination is a ratified standard. And that isn't marketing hype. You have to actually go to western digitals page and look at the spec sheet to find that info. It's not something they advertise as a feature.
Fine. So it's not hype. My point is that since these drives have not been in existence for 1.2 million hours (that's 137 years, mind you) how the hell can anyone make this claim with anything remotely resembling certainty? And if they can not be certain......well doesn't that bring us full circle right back to marketing hype?
EDIT: Sorry for the hijack.
not really hype,These disk drives have MTBF ratings of about 1,200,000 hours. This means that of all the drives tested, one failure occurred every 1,200,000 hours of testing.
Except that they couldn't possibly have tested any of the drives for more than a couple of years at *most* (think about it; you can't DO 1,200,000 hours of testing on an individual drive). What this MTBF figure means is they probably took, say, 250 drives, and tested them for, say, 5,000 hours straight (~6 months), which gives you 1.25 million drive-hours of testing, and they only had one drive fail (out of those 250) in that amount of time.
This does NOT mean the individual drives will last 1.2 million hours each on average -- it means that,
for a large enough population of drives, they expect roughly one failure per 1.2M drive-hours of usage, at least for brand-new drives. While this approach is valid, it does not generally take into account aging and wear on the drives (older drives get increasingly likely to fail -- it is unlikely that any current hard drives, no matter how well-made, will last more than 5-10 years under load), and without knowing more about the exact testing that's done (maybe they tested 1,000 drives for 1,250 hours each?, or 10,000 drives for 200 hours each?), it's hard to say how reliable these figures really are.