Re: How long does hard drive last?
- From: "Kerry Brown" <kerry@xxxxxxxxxxxxxxxxxxx*a*m>
- Date: Thu, 17 Nov 2005 16:21:49 -0800
Samsung says they calculate MTBF differently from your method:
http://www.samsung.com/Products/HardDiskDrive/whitepapers/WhitePaper_05.htm
They even mention an example:
" SAMSUNG's MTBF for HDDs is 500,000 hours. That means that if you use your
PC for 9 hours every day, your HDD should operate for 152 years. In
imperfect, non-test conditions, however, please note that the real life span
of an HDD varies because of fluctuating operating environments. "
Kerry
"David Candy" <.> wrote in message
news:u6koCN96FHA.2176@xxxxxxxxxxxxxxxxxxxxxxx
Your basic premise is wrong. MTBF excludes failures on new items (most) as
QA will pull them. It also excludes failure from age as it is irrelevent. It
is a measure on how reliable a thing is during it's lifetime.
So a hard drive is calculated thus
<testing - not counted><sale and use for next 5 years - counted><end of
lifetime of product - not counted>
If you want to measure average lifetime then measure that. MTBF doesn't
measure that (though it could - the maths is the same - but it would be
meaningless as a MTBF reliability figure).
MTBF lets Dell know they need x number of replacement drives in the next
year. As power on failures are generally excluded in MTBF and failure rates
tend to be constant during the rated lifespan Dell can work out how many
will fail in a year (and all are less than 1 year old) and include that in
their prices and spare parts stock levels.
--
--------------------------------------------------------------------------------------------------
Read David defending the concept of violence.
http://margokingston.typepad.com/harry_version_2/2005/10/entering_the_ga.html#more
=================================================
"NoNoBadDog!" <no_@xxxxxxxxxxxxxxxx> wrote in message
news:e88yu%2386FHA.1188@xxxxxxxxxxxxxxxxxxxxxxx
> David;
>
> Your analogy is not quite correct. MTBF stands for "Mean Time Between
> Failure". It is a mathematical construct used to determine, under ideal
> conditions, how long the *average* drive in a particular model series will
> perform before the drive suffers total failure.
>
> In the above explanation, it is important to understand that it is arrived
> at mathematically, not by rote testing. It also assumes the drive will be
> used under ideal conditions for the entire "life" of the drive. It
> relates
> to hardware failure, and not the number of read/write cycles are supported
> by the platters. A drive can suffer less than a total failure and still
> not
> have the data accessible (head damage from sudden movements would be an
> example); this scenario would not fall under MTBF because the mechanical
> parts still work.
>
> Some manufacturers offer a 1 year warranty, some offer 3 year warranties,
> and some offer 5 year warranties.
>
> The average home computer user obviously does not maintain the drive under
> ideal conditions.
> Some users never see a drive fail, some will have several fail.
>
> There is not way to predict how long *any* particular drive will last.
>
> That is why backups to other media (HDD, optical) should be part of the
> users backup regimen.
>
> Bobby
>
>
>
> "David Candy" <.> wrote in message
> news:Onei2u86FHA.1484@xxxxxxxxxxxxxxxxxxxxxxx
> MTBF is not a measure on lifetime. It is NOT
>
> total running time/number of units
>
> but the rate of failure. So a MTBF of 1000 hours would mean if you had
> 1000
> units running, on average one would fail every hour.
>
> --
> --------------------------------------------------------------------------------------------------
> Read David defending the concept of violence.
> http://margokingston.typepad.com/harry_version_2/2005/10/entering_the_ga.html#more
> =================================================
> "R. McCarty" <PcEngWork-NoSpam_@xxxxxxxxxxxxxx> wrote in message
> news:%23apog%23v6FHA.3660@xxxxxxxxxxxxxxxxxxxxxxx
>> The magnetic data retention is likely longer than the mechanics of the
>> drive. Most hardware has a MTBF (Mean Time Between Failure)
>> ratings. But that is an guesstimate/approximation by the manufacturer.
>> Use, storage, operating environment all affect how long it will last/run.
>>
>> Your question is very good. The transition from physical to digital
>> data is moving pretty fast. Many folks completely misunderstand that
>> a hard drive is not a permanent type of storage. I frequently encounter
>> folks who've lost photos, video or financial data because it only existed
>> on a PC's hard drive. Worse yet, are the ones who think they have a
>> reliable backup only to have it fail when called on for recovery.
>>
>> "Tsuniper-X" <TsuniperX@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:73AA3723-63E0-4263-B8FD-416A83902F7A@xxxxxxxxxxxxxxxx
>>> David Candy said:
>>>
>>> "CDs last from 2 to 50 years. Make two (on different brands) and test
>>> every
>>> two years. Shop bought CDs will last longer."
>>>
>>> Then my obvious concern goes to my little PEHD.(Personal External Hard
>>> Drive)
>>> How long does INTERNAL hard drives last? For EXTERNAL hard drives?
>>
>>
>
>
.
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