Fans and Hard Drives

[Ron Bogart]

In

Re. the later post about using Seagate, that's still a debatable
point, but personally I'd go for WD instead until someone eventually
PROVES to me that Seagate has as good a track record as WD.

The OP states that the failed drives were Maxtor. I have never had
much luck with Maxtor and have switched to WD, but I will have to
consider the Seagate warranty when I buy another drive. Seagate's is
5 years!!
FWIW, JAX

I have had nothing but trouble with the last 4 WD drives I bought - switched
to Seagate and haven't had another problem. For the record though, all 4 WD
drives that failed and failed miserable (including replacements) were 80 Gig
drives.

 

[johnf]

Interesting theory, but more than slightly slightly off-track.
The fans are powered from the Switching-mode power supply which outputs
various different (DC ONLY) voltages via different rails. Where on earth is
AC supposed to magically appear from?
Fans don't produce anything except airflow & PC fans have a DC motor to
power it - end of story!

I also have a suggestion as to where the capacitors should be inserted, but
currently am too polite to include that.

 

[johnf]

Oh, dear!
Have you ever done any AC/DC theory courses?
Refer to my reply in your other post to this thread if you wish.
Surely you mean 110VAC - not DC (EMF normally only applies to AC, by the
way).
I'd be interested to see how you (quote) - "nstalled a 110 VDC fan directly
to the PSU?? after the power switch", seeing the PSU outputs DC only & the
only 110V (AC - not DC) is prior to the input to the PSU, IOW, directly fed
from the mains cable, and completely unrelated to the PSU's function.
Terminology problem?
I have a feeling you're trying to say "go to the local Supermarket, buy a
small fan designed for personal cooling & stick that inside the PC case to
provide additional airflow?".

 

[Timothy Daniels]

A simple loss of power *has* been anticipated in modern
hard drive design, but *unsteady* power remains a problem
for any electronic device. Here is the traditional problem
with power loss for hard drives, and the modern *attempt* at
protecting against it, from http://en.wikipedia.org/wiki/Hard_drive:

"Head crashes can be caused by electronic failure, a sudden
power failure, physical shock, wear and tear, or poorly
manufactured disks. Normally, when powering down, a hard disk
moves its heads to a safe area of the disk, where no data is ever
kept (the landing zone). However, especially in old models,
sudden power interruptions or a power supply failure can result
in the drive shutting down with the heads in the data zone, which
increases the risk of data loss. Newer drives are designed such
that the rotational inertia in the platters is used to safely park the
heads in the case of unexpected power loss. In recent years,
IBM pioneered drives with "head unloading" technology, where
the heads are lifted off the platters onto "ramps" instead of having
them rest on the platters. Other manufacturers have begun using
this technology as well."

*TimDaniels*

It could, but I'm betting that it would not. Even when drives
were spinning at a lowly 4500 RPM the heads were
suspended by an "air cushion". The drive would have to
spin down to a almost dead stop while the heads were still
in the data area, and not in the park position.

I believe the designers of the hard drives would have
anticipated this scenario (-:

--

Regards:

Richard Urban

aka Crusty (-: Old B@stard

[.........] I don't think that the corresponding voltage drop caused
by the simultaneous starting of all the small motors would cause
physical damage to "any" of the devices (except maybe the
power supply itself - if it's built in protection doesn't kick in). It
may have the effect of creating hard drive sectors that contain
corrupted data - if the device were trying to write to the drive
at that particular instant. But, when the computer is starting from
an "off" state, the drives are reading information - not writing!

The read/write heads depend on a minimum speed for the
heads to "fly" (i.e. be held off the platter by the air wedged
between them and the platter). If the speed should drop
suddenly before the arm can be withdrawn, the heads will
"crash" (i.e. contact the platter), causing the whining sound
of death. It can be imagined that such a scenario would
occur if the voltage were to suddenly drop.

*TimDaniels*

 

[Richard Urban]

You are referring to a "power failure". We are considering the effects of a
voltage "drop" - which may still keep the platters spinning, but at a
reduced rate. The heads will still be floating on the air bearing till the
speed drops such an extent as to enable the mechanism to "park" the heads!
Hence, no crash.

There may be corrupted data due to low voltage in the drive electronics, and
then only if the drive is writing at the time of the voltage drop.

I have purposely reduced the drive voltage to 10 volts (via a divider
circuit) and have experienced no mechanical problems during the test. I have
experienced some loss of data though as I was able to successfully boot into
Windows 2000 at this reduced "drive" voltage (Windows was reading writing
during my test).

The 3 volt and 5 volts rails were not altered during this test.

--

Regards:

Richard Urban

aka Crusty (-: Old B@stard

A simple loss of power *has* been anticipated in modern
hard drive design, but *unsteady* power remains a problem
for any electronic device. Here is the traditional problem
with power loss for hard drives, and the modern *attempt* at
protecting against it, from http://en.wikipedia.org/wiki/Hard_drive:

"Head crashes can be caused by electronic failure, a sudden
power failure, physical shock, wear and tear, or poorly
manufactured disks. Normally, when powering down, a hard disk
moves its heads to a safe area of the disk, where no data is ever
kept (the landing zone). However, especially in old models,
sudden power interruptions or a power supply failure can result
in the drive shutting down with the heads in the data zone, which
increases the risk of data loss. Newer drives are designed such
that the rotational inertia in the platters is used to safely park the
heads in the case of unexpected power loss. In recent years,
IBM pioneered drives with "head unloading" technology, where
the heads are lifted off the platters onto "ramps" instead of having
them rest on the platters. Other manufacturers have begun using
this technology as well."

*TimDaniels*

It could, but I'm betting that it would not. Even when drives
were spinning at a lowly 4500 RPM the heads were
suspended by an "air cushion". The drive would have to
spin down to a almost dead stop while the heads were still
in the data area, and not in the park position.

I believe the designers of the hard drives would have
anticipated this scenario (-:

--

Regards:

Richard Urban

aka Crusty (-: Old B@stard

:
[.........] I don't think that the corresponding voltage drop caused
by the simultaneous starting of all the small motors would cause
physical damage to "any" of the devices (except maybe the
power supply itself - if it's built in protection doesn't kick in). It
may have the effect of creating hard drive sectors that contain
corrupted data - if the device were trying to write to the drive
at that particular instant. But, when the computer is starting from
an "off" state, the drives are reading information - not writing!


The read/write heads depend on a minimum speed for the
heads to "fly" (i.e. be held off the platter by the air wedged
between them and the platter). If the speed should drop
suddenly before the arm can be withdrawn, the heads will
"crash" (i.e. contact the platter), causing the whining sound
of death. It can be imagined that such a scenario would
occur if the voltage were to suddenly drop.

*TimDaniels*

 

[Dave VanHorn]

Voodoo electronics aside, the only thing a fan is going to do for you here,
is help you.
I've used 12V fans run on 5V, which makes them very quiet, and still gives
respectable airflow.

Having tried it, I'm really sold on water cooling.
You have no real airflow, so you don't get that buildup of microdust that
ruins the efficiency of any heat sink. The only dust buildup is at the
large radiator, which is dead easy to clean.
Since I built this water cooled system, I've had no failures in almost three
years(!)
For me, that's pretty miraculous. I'm used to drives or power supplies
failing about every 6 months.

 

[null]

IMHO, the warranty is meaningless if you don't have reliable backups.
The data on the drive is far more important to me than the drive itself.
If you have a good backup system in place - and you use it - then the
warranty has some value.

--
The reader should exercise normal caution and backup the Registry and
data files regularly, and especially before making any changes to their
PC, as well as performing regular virus and spyware scans. I am not
liable for problems or mishaps that occur from the reader using advice
posted here. No warranty, express or implied, is given with the posting
of this message.