Slashdot Mirror
Physical Hard-Disk Data Arrangements and Drive Failures?
Tadau asks: "Knowing not much of the low-level and molecular aspects of a hard drive platter, I'm wondering if it is possible to cause a weight change/imbalance on a hard drive platter by say writing solid 1's to approximately 1/2 of a side of the platter? If there is a weight change, then could that attribute to drive vibrations by an ever-so-slightly unbalanced platter, which may result in an eventual drive failure?"
I mean, seriously, does a one weigh more than a zero?
ymmv
c'mon guys, can't you create an April Fools thread with a bit more credibility... If I see this same story in this month's GamePro I'm gonna want my money back. 'from the theoretical-weight-of-information dept.' sheesh! let's just give it away from the start. oh well, better luck next year.
"If I wanted your input on my pet project, I'd stick my hand up your ass and use you like a sock-puppet." - Muse
The answer is yes. If you write all 1's to one side of a drive, and all 0's to the other side, the drive will eventually fail.
-- I have monkeys in my pants.
No.
If you could however write all 1's to all the harddrives in the Southern Hemisphere it would likely cause a polarity shift on the earth however. (AF)
"I figure you're here 'cause you need some whacko who's willing to stick his finger in the fan. So who are we helping?
For reminding me what day it is.
to an online utility and an explanation of how it works Hard Drive Balancer
Meddle thou not in the affairs of Dragons, for thou art crunchy and with most anything.
Come on, guys, most of these "joke" stories aren't even mildly amusing or convincing. They're just plain dumb. Put a little effort into it, will ya?
If all the hardrives were ones it would have the north and south poles more defined and the hard drive would cave in to itself.
The real risk is that if you write all ones to the entire surface of the disk, you will effectively create a spinning monopole. This will cause your data to 'go back into time' and erase itself.
"Eve of Destruction", it's not just for old hippies anymore...
RLL-encoding makes long strings of "ones" and "zeros" unlikely.
Back in the old FM days (where there was a direct relationship between flux and data) you might have had a problem such as you describe, but remember that the disks rotated at much lower RPMs then.
These days you don't have anything to worry about.
I'd be more worried about all those '1's standing up on that one half of the drive. This causes an aerodynamic drag imbalance that will induce harmonic vibration. Not only is the buzz annoying, I have heard from an aquaintance that the drive bearings will wear into an elliptical pattern causing all the cylinders on half the drive to be off-by-one. If the drive begins malfunctioning, tapping one side of the drive with a 20-oz. hammer will reset the bearing geometry.
Healthcare article at Kuro5hin
If you write on the platter it will depend on what ink you use...
You know, a 0 is bigger than a 1, so who's to say the 0s aren't heavier? Think of how many more atoms it must take to write that 0, not to mention the increased time...
I did not design this game/I did not name the stakes/I just happen to like apples/And I am not afraid of snakes-AniD
If you are really concerned, you will have to make sure the driver is going to write all data evenly to a drive. FAT, naturally, is a non-option due to its fragmentous nature, so perhaps anotehr file system that doesn't require frequent defragmentation - EXT2, EXT3, JFS, or (God Forbid) OS/2's HPFS.
This sig no verb.
PHB: This laptop computer weighs too much. Do we have anything lighter?
Wally: Why don't you just delete files to lower the weight on that one?
PHB (curiously studying laptop): That's a thought.
Wally: Technically, I only asked why not.
Beauty is in the eye of the beerholder.
Once a year, (traditionally, the first day in April) all disk and tape drives were rebalanced by redistibruting ones and zeroes. The "bit buckets" were also emptied on this hallowed day.
This isn't a problem anymore because all modern recording media use "MFM", "RLL", or "GCR" encoding methods, where ones and zeroes are automatically balanced.
One minor technical nit: "ones" actually weigh less than "zeroes". This led to the conclusion that the more data you put on your punched cards, the less they cost to mail :-)
On what file system your using. Modern file systems (like ReiserFS and ext3) take this into account and distribute the data accordingly using complex algorythms I don't pretend to understand. It's worth noting that fat16/32 don't have this problem either due to drive fragmentation. So if you use either of those two you're safe as long as you don't run a disk defrag tool.
Hi! I make Firefox Plug-ins. Check 'em out @ https://addons.mozilla.org/en-US/firefox/addon/youtube-mp3-podcaster/
Actually, because data is stored as 2's complement, the so-called "1" is actually a *negative* 1, causing it to actually levitate. This helps reduce friction on the disk, ultimately leading to fewer disk failures. Ahh, the wonders of modern science.
... those that are never turned on.
Infuriate left and right
What an excellent question. Not many people are as perceptive as you. As a matter of fact it does make a difference, starting at the 80 gigabyte 7200 rpm range and it was part of the Microsoft suite of nanocode system support that had to be worked on starting with Windows 2000. It is an automatic system service to move data sectors with low zero counts automatically to maintain 'Odd-Set Symmetry' known as OSS in the Windows world. Macintosh has something similar, I believe it's known as 'Bipolar Symmetry' or BS.
It is rumored that terrorists are working on various ways to defeat this part of the underlying system software, either by a worm or a simple user hoax that will lead to the disablement of high volume high speed drives. As larger and larger and faster and faster hard drives come to the market over the next couple years, you'll probably hear more about this iss.
It's always darkest just before it goes completely black.
And the story is apocryphal.
But it goes something like this:
In an early NASA launch project the engineers needed to know the exact weight of every component in the craft. The programmers swore that the software didn't weigh anything. The engineer in question finally slams down a bunch of punch cards in frustration and demands to know how much the software weighs.
The programmer replies, "We only use the holes."
There are more applications for harddrives. By letting the heads flow freely on the harddisk and look at the data it sees, you can measure your acceleration.
no -- the answer
I mod down anyone who says "I will be modded down for this", regardless of the rest of their comment