Newsgroups: comp.misc
Path: utzoo!utgpu!news-server.csri.toronto.edu!torsqnt!tmsoft!robohack!contact!slaurel
From: slaurel@contact.uucp (David Maxwell)
Subject: Re: Installing HDs upside-down
Organization: Contact Public Unix BBS. Toronto, Canada.
Date: Sun, 28 Apr 91 04:59:17 GMT
Message-ID: <1991Apr28.045917.14294@contact.uucp>
References: <1991Apr21.184024.13484@ecst.csuchico.edu> <MIKEG.91Apr23123100@c3.c3.lanl.gov>

In <MIKEG.91Apr23123100@c3.c3.lanl.gov> mikeg@c3.c3.lanl.gov (Michael P. Gerlek) writes:


>In article <1991Apr21.184024.13484@ecst.csuchico.edu>
>   ekrimen@ecst.csuchico.edu (Ed Krimen) writes:

>> I always had the impression that installing HDs upside-down was bad.  Then
>> so I'm assuming upside-down drives aren't a problem.
>> Is it preferable to install hard drives upside-down?!
>Doesn't make a (bit) of difference, because the bits are stored on the
>disk vertically, and an upside-down 1 or 0 is still readable as a 1 or
>0 - ones and zeros are vertically symmetrical.   :-) :-)
>Of course, you may wind up reading all your files backwards
>(endianness, et al)...

Well, while the positioning of a drive may have no effect on the magnetic
storage system used, because everything is relative to the position of the
drive, there is another matter. Hard drives contain a disk which spins
constantly, and at high speed. These two facors are part of the reason hard
drives are so fast. 1) No wait for spin-up time during each disk access
(As per floppy). 2) The disk is more durable, and encased in a 
dust/fingerprint/moisture-proof box, which means that the magnetic surface
is more reliable and is one factor which allows the data to be read at
the higher rotational speeds.

	Numbers one and two combine to set up a constant, fairly strong 
gyroscope, so moving the drive (aside from in the plane of rotation) while
it's on is a bad idea. Try holding a gyroscope and turning it in any direction
(Not in the plane of rotation) and feel the resistance. Imagine the 
gyroscope spinning much faster, and the resistance as pressure on the
surface of your hard disk's platter. Not good. 
	
	I'm not a physics major, but I've been told that the best positions
for the drive are 90 deg  angles, (I justify this by reminding myself that
the Earth is spinning too. (Maybe hardrives should only be mounted 
sideways in positions where they face north or south? :-) ) )
 
	So aside from that, remind yourself that hardcard makers mount
drives sideways daily, but that the hard drive manufacturers make them
with a side generally considered up. If it was better for your hardrive 
to be upside down, or sideways, wouldn't the manufacturer have called
a different side 'up'. (I have two hardrives mounted sideways in my machine,
one on it's left, on it's right.)

						David Maxwell

P.S. Would some kindly physics major like to discuss gyroscopic forces in
	terms of hard drives?

--
	Worf: I protest! I am NOT a merry man!   (Qpid)
						slaurel@contact

