hard disk off-level?

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I have a 250 GB hard drive that has the Dell "rails" on it. I wish to run
the OS and programs on this disk in a couple of different computers to
compare performance results.

It's easier for me to just slide the drive out of its native box and plug it
into the new machines as a master drive, but I don't wish to remove the
"rails". Is it OK to run the drive when it's at say, a 45 deg. angle or even
laying on it's side?

I don't know if gravity is absolutely required to be in a (relative)
downward direction for a drive to work properly.

Re: hard disk off-level?

Anita wrote:
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If in doubt, you can download the hard drive specifications from
the manufacturer. That is how I got this information, a number
of years ago.

At one time, "normal" mounting was all that was allowed. Older
drives only supported flat mounting.

    |        |

That has changed. Now, you're allowed "six axis" mounting.
You can lay a drive flat (like normal). You can tip it
on edge, so it is standing straight up.

But 45 degrees is not allowed.

These are some options. In the figure on the right, the
controller board can be on top or on the bottom. In
other words, the drive can be upside-down if you want
(subject to the controller board receiving some airflow).
Don't place the drive in an insulating cloth for example.
Try to allow some airflow.

    |  |
    |  |   +--------+
    |  |   |        |
    +--+   +--------+

You could also mount it, with the ribbon cable pointing
straight up, or straight down, but that is silly and
not practical. The two ways shown in the diagram
should be sufficient. The total count of orientations
should then be six, of which two are not useful, and
the four others are OK.

Commercial hard drive enclosures take advantage of these
options. Some drive housings mount in a stand, supporting
the "on edge" orientation shown on the left.


Re: hard disk off-level?

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uhmmmm, how do you explain a laptop/notebook sitting on a cooling stand or a
lap which can be anything from 10 through 45 degrees.

Re: hard disk off-level?

Eric Shune wrote:

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That is why I suggested looking it up. I was relaying what I read
in an OEM spec document, which is a more detailed document than
the single page you might get when buying the drive.

Here is an example of the wording. Some other wordings I found,
were more ambiguous. This was the clearest description I could
find today. In this case, the statement is on PDF page 46.


    "9.1 Drive orientation

         The drive may be mounted in any orientation. All drive performance
         characterizations, however, have been done with the drive in horizontal
         (disks level) and vertical (drive on its side) orientations, which are
         the two preferred mounting orientations."

So that says, sure, you can run that drive on a 45 degree angle. But if
the drive doesn't meet all its specs that way, they're off the hook.
What they're saying, is they test the drive flat or on its edge.

Actually, you should read documents like that, for every generation.
How the drive works inside, is changing with each generation.
For example, the servo writer port has disappeared on the side
of the drive. Hitachi is experimenting with zero flying height
heads. The material stackup on the platters is constantly changing.
And that could affect the robustness and sensitivity to environmental
conditions. So if someone asks this question in two years time,
another read of the spec for the new drive, might be a good idea.


Re: hard disk off-level?


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You cannot 'compare' results by switching an OS image between
machines. The OS gets installed and prepared for the hardware it
is installed on. Putting a harddisk with installed OS in may even
cause harm to your hardware.

And if the OS happens to be Windows (of any kind) you violate the
terms of use. (You may not care about that, but someone does. And
that someone has the abitlity to blacklist your key, disabling
this Windows copy on any installation :-)

If you want to compare performance, there is an easy way: run
some hardware profiling software from a life CD or USB boot key.
If you are lazy: just run memtest86. It will provide you with a
pretty accurate comparison !

Kind regards,
Gerard Bok

Re: hard disk off-level?

Anita wrote:
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Although back in the days of MFM drives...
position could make a difference...
todays drives can *absolutely* be used in any position

of course as mentioned it's a moot point
as with different H/W it's not likely Windows will even boot at all.

try your tests with Linux...
most of the new distros will reconfigure without a problem

Re: hard disk off-level?

Anita wrote:

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If you ever get a chance to tear open a junked HD, look at the heads
and notice their arms have springs that make them press firmly against
the platters.  Also if HDs need gravity, then why do Winchester HDs
(i.e., any HD with platters inside a dust-free chamber) work on the
International Space Station and, on Earth, when mounted upside down or
vertically?   The instructions I've seen from Seagate, WD, Samsung,
and Hitachi say it's OK to mount their products in any orientation.
The only possible problem should involve the head arm balance, and
very old Seagates were prohibited from being mounted with the front on
the bottom, and some instructions told customers to keep the drives
within 10 degrees of perfectly vertical or horizontal.

However you install the HD, make sure it's mounted securely and not
with just duct tape (i.e., Best Buy style) or nylon ties.  I prefer to
install drives vertically because when there's no fan air blowing
across them, their aluminum castings run a couple of degrees cooler,
and some of their chips can run 10-20 Celcius cooler.

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