HEWETT@sumex-aim.arpa (Mike Hewett) (12/17/85)
Given the distance between the head and the disk in state-of-the-art hard disk drives, I'm *certain* that the manufacturers do not count on gravity to maintain the distance. If so, then a hard disk manufactured near the equator would probably not work in North America because of differences in the force of gravity. So, although I'm not an expert, I would say that running a hard disk sideways or even upside-down should work okay. Mike Hewett (HEWETT@SUMEX-AIM) -------
MEAD@usc-eclb.arpa (Dick) (12/17/85)
Message-ID: <12167883923.27.MEAD@USC-ECLB.ARPA> The head-arm assemblies are built with flex tension forcing the head onto the disk platter and the heads are forced away and fly due to the turbulence caused by the spinning disk platters ( a very simplistic explaination, I know) so it does not matter which orientation the disk is in, other than to provide for ventilation or reduction of heat on the pc card attached Most disk makers state in their specs that orienation is not a factor. -------
hsu@eneevax.UUCP (Dave Hsu) (12/18/85)
In article <790@brl-tgr.ARPA> MEAD@usc-eclb.arpa (Dick) writes: >The head-arm assemblies are built with flex tension forcing the head onto >the disk platter and the heads are forced away and fly due to the turbulence >caused by the spinning disk platters ( a very simplistic explaination, I know) >so it does not matter which orientation the disk is in, other than to provide >for ventilation or reduction of heat on the pc card attached >Most disk makers state in their specs that orienation is not a factor. >------- On the other hand, the platter assembly is usually mounted directly to the bottom of the case, and some warpage occurs if too much heat builds up, affecting the angle between the heads and the platters. I'm not certain what effect mounting the drives sideways has on this warpage, but I suspect it may become worse as the the weight of the platters will torque the spindle instead of moving it towards the base of the drive housing. Comments? -dave -- David Hsu Communication & Signal Processing Lab, EE Department <disclaimer> University of Maryland, College Park, MD 20742 hsu@eneevax.umd.edu {seismo,allegra}!umcp-cs!eneevax!hsu CF522@UMDD.BITNET And then there were none.
grr@unirot.UUCP (George Robbins) (12/19/85)
In article <785@brl-tgr.ARPA> HEWETT@sumex-aim.arpa (Mike Hewett) writes: >Given the distance between the head and the disk in state-of-the-art >hard disk drives, I'm *certain* that the manufacturers do not count >on gravity to maintain the distance. so far so good... If so, then a hard disk >manufactured near the equator would probably not work in North >America because of differences in the force of gravity. sorry, the difference is negligible! >So, although I'm not an expert, I would say that running a hard >disk sideways or even upside-down should work okay. **** WARNING **** Many drives are spec'd to work in any orientation EXCEPT upside-down. The important factor is not the head loading, but the design of the bearings for the spindle. Running a drive upside-down may not destroy it, but I wouldn't recommend trying it on a drive you depend on. Also, please note that the bearing are fairly fragile and may be supporting a rather heavy mass. Sharp impacts are as likely to screw up the bearings as they are to crash the heads. -- George Robbins uucp: {unirot|tapa}!grr P.O. Box 177 Lincoln U, PA 19352 [Any ideas herein are not responsible for themselves!]
jbs@mit-eddie.UUCP (Jeff Siegal) (12/19/85)
In article <459@eneevax.UUCP> hsu@eneevax.UUCP (Dave Hsu) writes: >In article <790@brl-tgr.ARPA> MEAD@usc-eclb.arpa (Dick) writes: >>The head-arm assemblies are built with flex tension forcing the head onto >>the disk platter and the heads are forced away and fly due to the turbulence >>caused by the spinning disk platters ( a very simplistic explaination, I know) >>so it does not matter which orientation the disk is in, other than to provide >>for ventilation or reduction of heat on the pc card attached >>Most disk makers state in their specs that orienation is not a factor. >>------- > >On the other hand, the platter assembly is usually mounted directly to the >bottom of the case, and some warpage occurs if too much heat builds up, >affecting the angle between the heads and the platters. I'm not certain >what effect mounting the drives sideways has on this warpage, but I suspect >it may become worse as the the weight of the platters will torque the spindle >instead of moving it towards the base of the drive housing. > >Comments? > I seem to remember installing a 160 Mb 8" Fujitsu drive which had a switch one was instructed to set to 0 for vertical installation and 1 for horizontal installation. I have no idea what this switch did (if anything). Has anyone seen anything like this? Any ideas? Jeff Siegal - MIT EECS (jbs@mit-eddie)
tj@alliant.UUCP (Tom Jaskiewicz) (12/20/85)
In article <790@brl-tgr.ARPA> MEAD@usc-eclb.arpa (Dick) writes: >Most disk makers state in their specs that orienation is not a factor. True. However, some disks object to operating in any orientation other than the one in which it was formatted. -- +--------------------------------+ | uucp: decvax!linus!alliant!tj | +--------------------------------+ Bernese are mountains of love.
bmw@aesat.UUCP (Bruce Walker) (12/20/85)
> So, although I'm not an expert, I would say that running a hard > disk sideways or even upside-down should work okay. > > Mike Hewett > (HEWETT@SUMEX-AIM) NO! not upside-down. If you read the manufacturers specs for almost any hard disk drive, you'll find a section on mounting hardware and orientation. There, you'll see that just three orientations are recommended -- horizontally (generally with its circuit board down), or vertically on either side. +-------+ +-------+ | o | | | | | +------------+ | | | | | | | | | | | o | | o | +-------+ +------------+ +-------+ This mounting arrangement has more to do with heat dissipation and considerations of the motor bearings than for the head, which is held at a fairly accurate and constant 'n' microinches above the media by its aerodynamics (it literally "flies"). Some drives (like the CDC Wren series) should only be mounted flat or on *one* of its sides (see appropriate installation manual) because the drive has a gravity-operated head-zero spring which, when power is removed, pulls the head into its landing zone to protect it when it "lands" after the media spins down. --- Bruce Walker {allegra,ihnp4,linus,decvax}!utzoo!aesat!bmw "I'd feel a lot worse if I wasn't so heavily sedated." -- Spinal Tap