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Date:      Mon, 5 Jan 2009 04:01:07 +0100
From:      Erik Trulsson <ertr1013@student.uu.se>
To:        perryh@pluto.rain.com
Cc:        aryeh.friedman@gmail.com, glen.j.barber@gmail.com, freebsd-questions@freebsd.org
Subject:   Re: OT: how many rankmount units is a tower-case
Message-ID:  <20090105030107.GA72879@owl.midgard.homeip.net>
In-Reply-To: <49611f1a.WdTTi/Qznzkq5Qz3%perryh@pluto.rain.com>
References:  <4960B7D1.1070403@gmail.com> <4ad871310901040530r2a4c280ds188a679c815db657@mail.gmail.com> <4960BABA.4040705@gmail.com> <4ad871310901040535s5808ddfblcf356bfcb402cf2@mail.gmail.com> <a333b2be0901040944v6da44f63ie47c8dceff71166c@mail.gmail.com> <49611f1a.WdTTi/Qznzkq5Qz3%perryh@pluto.rain.com>

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On Sun, Jan 04, 2009 at 12:42:02PM -0800, perryh@pluto.rain.com wrote:
> > If a hard disk formatted and used in a position , in that position
> > it may be used if manufacturer is NOT advised a specific position.
> > After loading of files into hard disk , change of position may
> > cause difficulty in reading of already recorded data .  This point
> > should be considered .
> 
> Sun, at least, used to warn about this back in the MFM/ESDI days,
> recommending that a disk should be reformatted if its orientation
> were changed, but those drives used all their heads for data and
> depended on reproduceable mechanical positioning to align the heads
> at the selected cylinder.  I'm not sure it still applies to drives
> that dedicate one head to fine-tuning track position by reading
> factory-recorded servo patterns.  (Quick check, if "actual" geometry
> is known:  a drive with an odd number of heads most likely has a
> dedicated servo surface.)  BTW most drives of that era, while OK on
> either side as well as "right side up", were *not* supposed to be
> run "upside down" -- the bearings were not designed for that.

That may well have been true back in those days, but reasonably modern
drives[*] do not have those limitations. 

Todays drives can be mounted in any orientation, and should have no problems
being remounted in a new orientation. 


>From Western Digital's FAQ:

  Physical mounting of the drive:
  
  WD drives will function normally whether they are mounted sideways or upside
  down (any X, Y, Z orientation). Of course, the physical design of your
  system may limit the positions in which the drive can be mounted. However,
  in all cases, you should mount the drive with all four screws for good
  grounding. Also ensure that there is enough air space around the drive for
  adequate air flow, and avoid mounting the drive near sources of excessive
  heat (such as some CPUs).

>From Seagate's FAQ:

  All Seagate & Maxtor's internal hard drives can be fitted sideways or upside
  down. As long as they can not be moved during use and get enough cooling it
  is irrelevant in which direction they are mounted.


>From Hitachi's installation guide:

  There are many variations of system cases. Hitachi Deskstar
  drive can be mounted with any side or end vertical or hori-
  zontal. Do not mount the drive in a tilted position.







[*] "resonably modern drives" includes just about all drives any sane person
would even consider using for a new computer build.

-- 
<Insert your favourite quote here.>
Erik Trulsson
ertr1013@student.uu.se



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