External Hard drive - very basic question

  • Thread starter Thread starter Kate
  • Start date Start date
K

Kate

I recently purchased my first external HD. Can anyone tell me how
long the data will survive intact once the drive is unplugged from the
electricity supply, or is this something that varies depending on
model and make, please?

Many thanks
Kate
 
It will stay as long as you want it to. Having power on the drive doesn't
effect the contents.
Neil
 
Kate said:
I recently purchased my first external HD. Can anyone tell me how long the data
will survive intact once the drive is unplugged from the electricity supply, or is
this something that varies depending on model and make, please?

Many thanks
Kate
Click to expand...

Disconnecting the power is not a factor of data corruption/degradation unless it's
not disconnected properly. Where and how the disconnected drive is stored is a
factor which depends on room temp, moisture, objects near it, etc. When stored
properly it could last anywhere between shortly after disconnecting it up to approx
10yrs depending on the integrity of the drive.


--

Brian A. Sesko { MS MVP_Shell/User }
Conflicts start where information lacks.
http://basconotw.mvps.org/

Suggested posting do's/don'ts: http://www.dts-l.org/goodpost.htm
How to ask a question: http://support.microsoft.com/kb/555375
 
Brian A. said:
Disconnecting the power is not a factor of data
corruption/degradation unless it's not disconnected properly. Where
and how the disconnected drive is stored is a factor which depends
on room temp, moisture, objects near it, etc. When stored properly
it could last anywhere between shortly after disconnecting it up to
approx 10yrs depending on the integrity of the drive.

Brian A. Sesko { MS MVP_Shell/User }
Conflicts start where information lacks.
http://basconotw.mvps.org/

Suggested posting do's/don'ts: http://www.dts-l.org/goodpost.htm
How to ask a question: http://support.microsoft.com/kb/555375
Click to expand...

The reason I was asking is two-fold : as I am using the HD for
backups, it only needs to be connected to the power for about 1 hour a
day while the backup runs. At the moment, the drive spins up whenever
I go into Explorer, for example, and I have heard that spinning up and
down can damage the disk. Also, because of the shortness of the USB
lead, the drive has to stand close to the front of my CRT monitor. I
know that these monitors have a magnetic field, so wondered if it
could be a problem - although a device which sits on a desktop
*should* have some sort of shielding, I would have thought (?)

Thanks for the replies
Kate
 
The reason I was asking is two-fold : as I am using the HD for
backups, it only needs to be connected to the power for about 1 hour a
day while the backup runs. At the moment, the drive spins up whenever
I go into Explorer, for example, and I have heard that spinning up and
down can damage the disk. Also, because of the shortness of the USB
lead, the drive has to stand close to the front of my CRT monitor. I
know that these monitors have a magnetic field, so wondered if it
could be a problem - although a device which sits on a desktop
*should* have some sort of shielding, I would have thought (?)

Thanks for the replies
Kate
Click to expand...


Yes the harddrive is shielded and the monitor won't hurt it
 
Kate said:
The reason I was asking is two-fold : as I am using the HD for
backups, it only needs to be connected to the power for about 1 hour a
day while the backup runs. At the moment, the drive spins up whenever
I go into Explorer, for example, and I have heard that spinning up and
down can damage the disk. Also, because of the shortness of the USB
lead, the drive has to stand close to the front of my CRT monitor. I
know that these monitors have a magnetic field, so wondered if it
could be a problem - although a device which sits on a desktop
*should* have some sort of shielding, I would have thought (?)

Thanks for the replies
Kate
Click to expand...

Hard drives are resistant to erasure by adjacent magnetic fields. If
there was going to be an issue, it would be if the switching noises
from the flyback of the CRT, got coupled into the controller board
on the hard drive. (I had a TV set years ago, that if you waved a
fluorescent tube near the side of the set, it would light up. That
would be an example. But at least some computer monitors are
shielded on several sides, making that less of an issue. My Sony
has a plastic outer shell, and metal boxes inside to hold stuff,
so that helps contain that kind of interference.

Otherwise, it is pretty hard to completely erase a drive with an
externally applied magnetic field. An article I was reading on
secure erasure of hard drives, claims that for the latest generation
of drives, they can no longer guarantee that commercial degaussers
are powerful enough to be certified to do the job. Sitting next
to your CRT, the field is not quite as powerful.

Hard drive storage is non-volatile, so the drive does not need to be
powered to retain its contents. If you use the "Safely Remove" icon
for example, that flushes the cache and prepares the system for
proper removal. Then you can unplug it, and put it away.

In terms of "start/stop" rating, hard drives now have a boiler plate
spec, that the drive is rated for 50,000 start/stop cycles. So if
the drive "wakes up" and spins up, and later spins down again, you
can do the arithmetic and figure out how many years it can sustain that
kind of usage.

HTH,
Paul
 
Paul said:
Hard drives are resistant to erasure by adjacent magnetic fields. If
there was going to be an issue, it would be if the switching noises
from the flyback of the CRT, got coupled into the controller board
on the hard drive. (I had a TV set years ago, that if you waved a
fluorescent tube near the side of the set, it would light up. That
would be an example. But at least some computer monitors are
shielded on several sides, making that less of an issue. My Sony
has a plastic outer shell, and metal boxes inside to hold stuff,
so that helps contain that kind of interference.

Otherwise, it is pretty hard to completely erase a drive with an
externally applied magnetic field. An article I was reading on
secure erasure of hard drives, claims that for the latest generation
of drives, they can no longer guarantee that commercial degaussers
are powerful enough to be certified to do the job. Sitting next
to your CRT, the field is not quite as powerful.

Hard drive storage is non-volatile, so the drive does not need to be
powered to retain its contents. If you use the "Safely Remove" icon
for example, that flushes the cache and prepares the system for
proper removal. Then you can unplug it, and put it away.

In terms of "start/stop" rating, hard drives now have a boiler plate
spec, that the drive is rated for 50,000 start/stop cycles. So if
the drive "wakes up" and spins up, and later spins down again, you
can do the arithmetic and figure out how many years it can sustain
that
kind of usage.

HTH,
Paul
Click to expand...

That is all very re-assuring so I can stop worrying (about that,
anyway!). If my HD cycles an average of 7 times a day, then I figure
it ought to last for 19.5 years, which is more than enough for me and
would probably surprise the manufacturer no end :-) My thanks to
everyone for your help.

Regards
Kate
 
Paul said:
Hard drives are resistant to erasure by adjacent magnetic fields. If
there was going to be an issue, it would be if the switching noises
from the flyback of the CRT, got coupled into the controller board
on the hard drive. (I had a TV set years ago, that if you waved a
fluorescent tube near the side of the set, it would light up. That
would be an example. But at least some computer monitors are
shielded on several sides, making that less of an issue. My Sony
has a plastic outer shell, and metal boxes inside to hold stuff,
so that helps contain that kind of interference.

Otherwise, it is pretty hard to completely erase a drive with an
externally applied magnetic field. An article I was reading on
secure erasure of hard drives, claims that for the latest generation
of drives, they can no longer guarantee that commercial degaussers
are powerful enough to be certified to do the job. Sitting next
to your CRT, the field is not quite as powerful.

Hard drive storage is non-volatile, so the drive does not need to be
powered to retain its contents. If you use the "Safely Remove" icon
for example, that flushes the cache and prepares the system for
proper removal. Then you can unplug it, and put it away.

In terms of "start/stop" rating, hard drives now have a boiler plate
spec, that the drive is rated for 50,000 start/stop cycles. So if
the drive "wakes up" and spins up, and later spins down again, you
can do the arithmetic and figure out how many years it can sustain that
kind of usage.

HTH,
Paul
Click to expand...
Paul, since you did not mention it, I feel sure the OP and I both wish
to know your feelings on which would "likely" be better--to cycle it 7 times
per day, as OP estimated, or plugin/unplug once per day? Thanks for your
ideas. sdlomi2
 
sdlomi2 said:
Paul, since you did not mention it, I feel sure the OP and I both wish
to know your feelings on which would "likely" be better--to cycle it 7 times
per day, as OP estimated, or plugin/unplug once per day? Thanks for your
ideas. sdlomi2
Click to expand...

If you don't want to unplug it, you could always use one of those
"USB switch" devices. Once the USB path is disconnected, then Explorer
won't be waking it up. There are some USB switching devices, intended
for sharing peripherals between two PCs, and by using one of those,
you can make a crude USB disconnector. That saves wear and tear on the
plug. (You still have to do "Safely remove" before hitting the switch,
but then the drive can "go to sleep" and stay asleep.)

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Description=usb+switch&x=0&y=0

As for the externals, I've looked at some of the reviews on Newegg.com
and there seem to be quite a few reports of failures. It would seem,
that a limited number of the 2.5" units are good. I think the WD
Passport 2.5" 160GB unit had a clean bill of health. (It could be that
the 2.5 watt power rating of the drive, helps.) Strangely, some of
the lower capacity ones didn't have as good reports.

For 3.5" enclosures, one of my requirements is fan cooling, and proper
intake vents for good air flow. I'm not in favor of "aluminum
slab" designs for enclosures. There are, after all, some
hard drives that have had defective motor controllers on them,
and the motor controller IC overheats. Using an enclosure with
bad cooling characteristics, doesn't help matters.

Paul
 
Paul said:
If you don't want to unplug it, you could always use one of those
"USB switch" devices. Once the USB path is disconnected, then
Explorer
won't be waking it up. There are some USB switching devices,
intended
for sharing peripherals between two PCs, and by using one of those,
you can make a crude USB disconnector. That saves wear and tear on
the
plug. (You still have to do "Safely remove" before hitting the
switch,
but then the drive can "go to sleep" and stay asleep.)

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Description=usb+switch&x=0&y=0

As for the externals, I've looked at some of the reviews on
Newegg.com
and there seem to be quite a few reports of failures. It would seem,
that a limited number of the 2.5" units are good. I think the WD
Passport 2.5" 160GB unit had a clean bill of health. (It could be
that
the 2.5 watt power rating of the drive, helps.) Strangely, some of
the lower capacity ones didn't have as good reports.

For 3.5" enclosures, one of my requirements is fan cooling, and
proper
intake vents for good air flow. I'm not in favor of "aluminum
slab" designs for enclosures. There are, after all, some
hard drives that have had defective motor controllers on them,
and the motor controller IC overheats. Using an enclosure with
bad cooling characteristics, doesn't help matters.

Paul
Click to expand...

Over-heating *might* be a problem with my HD. It is a 500GB FreeAgent
Desktop - plastic case and (apparently) a metal mesh cage inside. No
fan that I can hear, unless it only works when the drive spins up. The
only vents that I can see are in the base, which seems illogical, as
hot air rises; and if they are intake vents for a fan, there is no
exhaust aperture. I have started running it for about one and a half
hours a day and the case gets warm-ish, certainly not hot. I have
read people complaining that this HD gets very hot, though, but they
did not say how long they were running it for. Re the USB switch you
mentioned, Paul, that will be worth looking into I think, not only for
the HD, so thanks for that.

Regards
Kate
 
Kate said:
Over-heating *might* be a problem with my HD. It is a 500GB FreeAgent
Desktop - plastic case and (apparently) a metal mesh cage inside. No
fan that I can hear, unless it only works when the drive spins up. The
only vents that I can see are in the base, which seems illogical, as
hot air rises; and if they are intake vents for a fan, there is no
exhaust aperture. I have started running it for about one and a half
hours a day and the case gets warm-ish, certainly not hot. I have
read people complaining that this HD gets very hot, though, but they
did not say how long they were running it for. Re the USB switch you
mentioned, Paul, that will be worth looking into I think, not only for
the HD, so thanks for that.

Regards
Kate
Click to expand...

What I do:
Turn on and use the external drive after I boot XP for that day. Turn off
the external drive before shutting down XP for the day.

What I use:
My own choice external case. My own choice hard drive that I fitted in that
external case.

Method of turning the external case on/off: Under monitor power station. I
never touch the external case or the power plug.
Dave
 
Kate said:
The reason I was asking is two-fold : as I am using the HD for
backups .......
Click to expand...

Kate,
Then you definitely want to look towards web based backup services.
Several of these are already available and more will arrive soon.
These services do all chores that are challenging for a typical home
or small business users.

Regards,
--PA
 
Thanks for the suggestion, Pavel, but I have been doing daily backups
for several years so I am reasonably au fait with the procedure now,
and scheduling reduces the chore considerably. Not only do I run a
Full backup daily, but I also burn My Documents to DVDs regularly.
These are neither encrypted nor zipped so are readable virtually
anywhere. I know it`s old-fashioned of me, but I would be very
reluctant to entrust the safety and privacy of my precious photos, for
example, to an unknown third party.

Dave : I was going to build my own external HD, but was advised that,
although it was fairly easy, it was "fiddly", so I backed off from
that idea.

Kate
 
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