How long does hard drive last?

[Guest]

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?

 

[R. McCarty]

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.

 

[Shenan Stanley]

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?

You just asked, "How many licks does it take to get to the center of a
Tootsie Roll Pop?"

Depends on environmental and external factors as well as possible internal
(manufacturer defect) factors. Use and abuse play heavily.

If your "Personal External Hard Drive" is a static RAM drive (Thumb drive
with no moving parts) - it will outlast (under perfect conditions) the one
with moving parts every time.

If it is a "drive in a box" - then it will last as long as your internal
hard drive would - if you picked up and moved your computer case around as
much and in the same way as you will that external box. Why? Same drive is
in that box as is in your computer.

So.. answer....

"One... Two... Three... *crunch*"
*grin*

 

[Guest]

you burn a CD the data on that CD is quite capable of lasting over 100
years. There really isn't anything to wear on a CD and the metallic surface
that is burnt may deteriote a bit depending how well the Plastic coating
lasts.
The Hard DRives whether Internal or External have moving parts and are
considered to be Mechanical and therefore if you get more than 2 years, be
thankful. I would put the max life of a Hard drive to be about 5 years and
that is in a daily used computer. The Discs are made out of thin kayer of
mykar and they should last about 20 years but will start to degenerate almost
as oon as they are reocrded on. I make it a habit to to erase and reload my
Hard dirve that is used for back up once per year. Digitial does not loase
quality when you make a copy of it, so my music doesn't get worst if I make a
second generation copy of it. The mechanics of the Hard drive may well last
over 5 years and I am sure there are millions that have. As far as trusted
data accuracy with the prolong life of a HD, I would NOT. They are cheap
enough that ity would be cheap insurance to buy a NEW drive every 5 years and
dump the data from the older to the Newer and use the OLDER as a seldom used
backup.

 

[Kerry Brown]

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?

Internal drives usually have a longer power on life. They usually have
better cooling and don't get jostled very much. The downside is they are
powered up for longer periods. Given all that most modern hard drives last
somewhere between a few days and several years before they fail. The moral
is don't rely on one backup method.

If you are looking for archival storage for many years then archival quality
CD or DVD's are the way to go. As David said they need to be tested and
possibly put onto new media every couple of years. There are two reasons:
First the media may be losing it's ability to store the data. Second the
media may be becoming obsolete. The hardware to read it may be getting hard
to get.

Kerry

 

[Generalisimo]

They are prone to failure the day after the warranty expires. If
you get by that milestone, you could get several years out of the
beast.

 

[Jim]

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?

These questions are closely related to "How long is a piece of string?".
Durability is a wearout problem. Some won't last long' others last for
years.
Jim

 

[Vanguard]

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?

Are you going to leave it running 24x7 which means the bearings continue to
wear while you are not using the computer?

If you power it down and up, how often do you do that? Each time there is a
surge current (the initial inrush), the low-torque motor's current is high
until the platters get up to speed, lube is cold on start, spindle wear
causes heat (besides the normal heat generated by the components) which
causes thermal stress, and so on.

How often are you banging around the drives, especially the external ones?
How cold is the room compared to the running temperatures of the devices
once warmed up? What anti-static precautions have you taken? Do you have
cats, dogs, or carpet in your house that increases the amount of dust,
dander, and lint that will collect inside your computer which acts as a
thermal insulator (and keeps the heat *at* the device rather than letting it
conduct away)? How often do you clean the inside the case, do you blow out
or dangerously use vacuums which generate static at the tip of the hose due
to the inrush of air, and do you use an anti-static wristwrap?

Do you have adequate surge protection (not a UPS) to prevent damage when you
leave the computer always powered on? Is it end-point surge protection
(i.e., a surge protected power strip or module sitting between your computer
and the wall outlet), or is the surge protection provided at the
point-of-entry for power coming into your domicile? If it is end-point
connection, and if you use more than one, are they connected in series or do
you have them in parallel (i.e., are they plugged together or separately
plugged into the wall outlet and maybe even into different wall outlets)?
If not in series (which means only the first one is really the one one that
needs to provide surge protection), the difference in lengths of wire
(between the wall outlets and for the cord to the surge protected power
strips) means the impedance of those lengths can result in several hundred
volts difference which is itself a surge. If you have an analog modem, is
there surge protection on the phone line, too, so it can't come in that way?
What other devices do you have the computer connected to and how are their
power connections setup?

Which file system do you use? FAT or NTFS? FAT gets defragmented and ends
up with the heads banging for the farther travel required to access the
fragmented pieces of a file? How often do you defragment your drive? Do
you think that fragmenting should have all files moved to the front of the
disk platter or rather just make sure the clusters for the file are
contiguous but can be just about anywhere on the platter?

How much air flows over the drive to cool it off? Does unheated air get
delivered over the drive, or are there other components that preheat the air
before it circulates over the drive? How much space is between the hard
drive and other devices in the other bays (i.e., back to how mush air flows
over the drive)? Does it run hot? Some drives spin faster than others, and
the faster spinning ones are usually hotter, so you need to cool them
better. Do you start it up in a very cold room? What's the MTBF that the
manufacturer claimed for the drive? Quality control during manufacturer and
consistently in quality affect how large is the deviation in the actual MTBF
experienced by you their customer, along with how the drive was handle
during transportation and storage. How many platters are inside that the
motor has to spin up? Do you let the system go into Standby or Hibernate
modes where the drive will stop spinning and then spin back up when the
system is no longer idle?

How much ripple is on the power tap connected to the hard drive from the
power supply (i.e., how well is that voltage regulated)? Is the voltage
on-spec?

How many times are you going to rewrite the same spot on the drive (i.e.,
toggle the dipole)? Magnetic hysteresis and retention wane over time (the
magnetic media tires). Even under NTFS, it is still a good idea to defrag
once in a while or rewrite all your drives to refresh and reinforce the
dipole. Data that is never used will lose its retention and lower the
chance of being reliably read later (one of the functions of SpinRite is the
refresh the media everywhere).

You could go by the manfacturer's MTBF for the device but then they test
under lab conditions, not with cat hair floating everywhere, carpet lint
tossed into the air, kids slamming the box, you trusting the moving company,
living near an industrial plant with huge lathes that push surges back into
the power grid and to your house, and so on.

It's a crap shoot. Figure the drive will fail early, like when you get it
or from 1 week to a month, or it will last for years but perhaps not much
longer than the MTBF or warranty period.

 

[Pegasus \(MVP\)]

My experience says otherwise. I have dealt with several burnt
CDs that were fine to start with but became partly or totally
unreadable after a while. I suspect it's not a question of
something "wearing out" but of the burnt layer deteriorating
over time. Note that many suppliers of blank CDs warn
specifically not to use certain pens when marking CDs. This
confirms that there is a chemical interaction between the surface
of a burnt CD and the environment.

On the other hand I find that hard disks are far more reliable.

 

[Jonny]

CD media is equivalent to the platter(s) on a hard drive, but has other
parts to break. It does not rely on the magnetic properties of the media
like a platter. Rather, the reflectivity properties. If not scratched or
otherwise damaged, will hold data for quite sometime beyond a hard drive
platter. Requires a cd reading device to acquire the data. A hard drive
has the media and the rotating movement, heads, interface all in one.

Scsi hard drives, generally more expensive per GB, may last over ten years.
Ide drives typically last less than half of that. Some hard drives built
today are dollar specials that weren't at all built for long term
reliability, pushing a reduced life for overall bigger replacement market.
The hard drives in both USB and Firewire externals are ide drives. The
difference is greater potential and more frequent rough handling compared to
an internal ide drive, and if the enclosure's power supply glitches and
damages/destroys the input circuitry. SATAs are too new to the market to
make a long term overall assessment.

A hard drive made by "Jupiter" lasted only 2 months in one Acom Firewire
enclosure here. A couple of ide hard drives I have are pushing 5 years, and
one scsi the same.

 

[Guest]

(From [Tsuniper-X])
Thanks for your replies people...but i still need a solid answer...

 

[Shenan Stanley]

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?

(From [Tsuniper-X])
Thanks for your replies people...but i still need a solid answer...

There is no "solid answer".

It's like you asking "How long will this rock last" and not giving any
further details.

- Are you sealing it in a vacuum bag, in a sealed metal safe encased in 6ft
of concrete?
- Are you putting it on the dash of your car?
- Will it be moved around?
- Will it be exposed to the elements - if so - what elements?
- Will you be touching it?
- Will anyone else be touching it - and how often?
- What elevation do you live at?
- Will you ever move?

Your "PEHD" (as you put it and never explained further - for example - is it
a static ram drive or one with moving platters?) will last as long as it
lasts in your environment given its level of use, exposure to different
situations, treatment and so on.

 

[David Candy]

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.

 

[R. McCarty]

It is an "Average" TIME between Failures and using your example
it would take 1000 hours of use before a "Single" Drive failed, not
1 drive out of 1000 running for one hour.

"David Candy" <.> wrote in message
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.

 

[NoNoBadDog!]

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
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.

 

[David Candy]

Wrong. It is not a measure of lifetime. Most failures happen in the first hour/first power on (and they are excluded if QA would normally pull them). It is a measure of reliability.

An item may have a average lifetime of 5 hours and a MTBF of 1000. Because in those 5 hours it has a 5/1000th chance of breaking. Note MTBF is calculated over the design lifetime. So for hard drives failures in the twentieth year aren't counted.

In practise most failures happen at the beginning or end of a products lifetime.

 

[Guest]

(From [Tsuniper-X])
Well, i DID explain that PEHD stands for Personal External Hard Drive. If
you have Seagate 40GB PEHD, it would be awesome. Anyway, this PEHD is
USB-powered, so the device turns on as soon as i connect it to the computer,
obviously, while the computer is on. i use this PEHD mainly for data backup,
although i'm sick of sharing computer with my sister because of "my" way of
controling the computer.(Account settings, an ATTEMPT to assign a partition
as a personal drive for many people-you would know what this means if you go
to school, most school computer supports this method-, disabling
right-clicking, download permissions, etc.)

i have no pet, no elements(IDK why this subject had popped up), i live in
east coast of U.S., HOPEFULLY less than half a mile above sea level. i keep
my PEHD inside the box that kept PEHD until i bought it, like an egg-holder
that holds egg. i keep this box inside my closet until i have further NOTICE.
i format this PEHD quite often, because i THINK it's better than just
deleting the files, and i'm pretty worried about "abusive" formatting right
now.

The basic question is "What is the maximum time the hard drive can keep data
to itself?" i hate myself for not questioning in this way, but now i did
anyway. This question has been rising up after the realization of "CD's won't
last forever", which concerned my PEHD because that's the only backup system
i can...rely!

i now realize that i should have asked this question to computer hardware
manufacturers, but it's too late. i asked this to Newsgroup because i THINK i
have heard that the maximum time the hard drive can keep data to itself was
less than a day in about 30 years ago, and gradually increased with better
technology. The point of this question is "What keeps data?" i'm simply
looking for an ABSOLUTE backup system.

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?

(From [Tsuniper-X])
Thanks for your replies people...but i still need a solid answer...

There is no "solid answer".

It's like you asking "How long will this rock last" and not giving any
further details.

- Are you sealing it in a vacuum bag, in a sealed metal safe encased in 6ft
of concrete?
- Are you putting it on the dash of your car?
- Will it be moved around?
- Will it be exposed to the elements - if so - what elements?
- Will you be touching it?
- Will anyone else be touching it - and how often?
- What elevation do you live at?
- Will you ever move?

Your "PEHD" (as you put it and never explained further - for example - is it
a static ram drive or one with moving platters?) will last as long as it
lasts in your environment given its level of use, exposure to different
situations, treatment and so on.

 

[David Candy]

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.

 

[Kerry Brown]

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
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.

 

[David Candy]

It's not MTBF then.