View Full Version : Hard drive "flat spots"
12 December 2003, 05:00 AM
I remember hearing years ago (in the 40MB days) that running hard drives in unusual positions, e.g. sideways, or upside down) could cause the drive bearings to develop a flat spot, causing alignment issues. Is this an issue for modern drives? Was it ever an issue?
I've been running a Western Digital 120GB drive *diagonally* for about a year for lousy form factor reasons (only three 3.5" bays while all the 5.25" bays are out of UDMA cable reach, and I have 4 HD's) and while it's running fine and hasn't manifested any changes in noise, it still is rather loud.
I just relocated it to alleviate airflow issues, so it is now screwed to the inside rear wall of the case, with it's "foot" (connector end) facing up.
Yes, it's backed up.:D
12 December 2003, 05:40 AM
Well, on the screen savers, leo said, that if a drive is formatted while it is sitting vertically, and then the drive is flipped horizontally, then you will run into problems...
because the minute amount of 'play' that the reader heads have, will cause the arms to hit a slightly different sector of the platter
12 December 2003, 01:45 PM
I have a feeling that it isn't a problem anymore as think about those portable enclosures. You stick a normal HD in them and they are supposed to be operatable vertically, laying flat, whatever.
12 December 2003, 02:54 PM
It shouldn't be an issue these days. Maybe back in the days of 8 1/8" thick platters in one drive for 40 megs... Nowadays, If you open up a drive, those heads barely move vertically, and with the platters spinning at over 7500rpm, the gimble effect keeps them from stressing any one area of a bearing (not to mention most bearings spin so you cant get a flat spot). Most are liquid drives also. There is also a vacume affect created from the spinning platters that helps keep everything in line. I wouldn't advise moving a drive around while its writing though, just not good practice. Bigger drives aren't built to be mobile like laptop drives.
12 December 2003, 03:43 PM
Someone once told me....
"You can mount the drive in any position you want...but after you format/partion it...Don't MOVE it from that position"
Aka if you have it running upside down, and you format it upside down, don't later flip it right side up.
I doubt this applies anymore, but what the hey...old admin stories of goodness.
12 December 2003, 05:40 PM
Harddrive bearings have become much better over the years. However afaik the last real no no is to run a standard 3 1/2" driver head over. Everything else should work and there should be no problem in changing the drives orientation after formatting.
Notebook drives are no problem at all, they are designed to work in every whitch way. Since their platters have a much lower mass and the rotation speed is usualy slower its easier by default.
12 December 2003, 11:38 PM
Orientation and Mounting (http://www.storagereview.com/guide2000/ref/hdd/op/packOrientation.html)
"Older hard disks that used stepper motor actuators were much more sensitive to orientation. It was in fact often recommended that the low-level formatting of the disk always be done after the disk was installed in its operating position, to avoid any shifting of the location of the tracks that might be caused by changing the orientation. Since hard disks today are much more solidly built, and they use voice coil actuators for dynamic head positioning, this really is not an issue. A modern hard disk can be side-mounted in the case without any problems, and can also have its orientation changed after it has been in use for some time."
http://www.lostcircuits.com/hdd/hdd2/3.shtml > Servo Bursts
"Briefly, a "Servo Burst" is a wedge shaped sector of the platter that contains protected positional data that are being read by the head and fed into a close-loop feedback circuitry to the servo controller for adjusting the head's positioning on the target track. What this means is that the data areas on each track are interrupted by wedge shaped areas that hold the positional data. Those Servo Bursts are factory -installed / protected and cannot be erased / modified by the user. Early HDDs did not feature Servo Bursts, instead, amongst the multiple platters, one platter was dedicated to holding only positional data. Since all heads are moving in unison, this solution did suffice as long as the TPI (tracks per inch) density was relatively low, meaning that head positioning did not require ultimate precision"
modern drives can be mounted and remounted in any orientation
without the need to reformat
01 January 2006, 11:00 PM
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