Memory and erasure of hard drives

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Indeterminacy
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Memory and erasure of hard drives

Post by Indeterminacy »

I worked for a large tech giant many moons ago. When we had hard drive issues it often was easier to wipe the drive
and start fresh. We used industrial degaussers that would lay waste to ones and zeroes. Typically two times as a matter or course.

I still wonder where did the data go. Deleting something isn't the same as degaussing. Overwriting isn't the same as degaussing.

What happened to the data?
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Re: Memory and erasure of hard drives

Post by crochambeau »

Indeterminacy wrote: Wed Jun 15, 2022 8:30 am What happened to the data?
The data was imprinted in pattern, that pattern was like a sand painting. Degaussing is like the wind.

The data essentially melted into a larger dynamic state wave that dissipated into heat, sound, and a residual magnetic imprint from which no delicate nuance can be derived.
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Re: Memory and erasure of hard drives

Post by NoiseWiki »

Indeterminacy wrote: Wed Jun 15, 2022 8:30 am What happened to the data?
I think there's alot of variables here.. depends on the storage medium and the operating system but when you "delete" a file it's still on the drive. Now as to whether or not it's recoverable may depend on where it was located on the platter and how much use the drive has had since you deleted it and how fragmented the file was. The more the drive is used the more likely some part of the file will have been written over. If the file was fragmented and the directory that keeps track of all the parts is corrupted you may never put humpty back together again. Then there are raids where it gets even more complicated because parts of the files may be spread across multiple drives.

I've read that with magnetic storasge mediums it is possible to read files that have been zero'd out. I can sorta see that as being possible based on working with tape cassettes and how you would often hear ghostly remnants of thing syou have recorded over (Jonestown death tape is a great example of this.. the reel to reel tape he recorded the day of the mass myself was recycled and he recorded at a slower speed so you hear all these slowed down artifacts under his voice). Anyway I imagine that with the amount of data and the types of media that can be stored these days that it's not really practical to do this without really good reason. I mean imagine a 20mb harddrive might be easy to recover some text files despite them being zero'd out multiple times but finding working files on a 3TB hd probably not so much.

Having said that.. read an article awhile back about how criminals have bought used photocopiers because modern ones have scanners in them and a harddrive and those harddrives are usually loaded with whatever had been scanned and it's a good source for personal info they can use to steal identities etc.
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Re: Memory and erasure of hard drives

Post by Indeterminacy »

crochambeau wrote: Wed Jun 15, 2022 9:19 am
Indeterminacy wrote: Wed Jun 15, 2022 8:30 am What happened to the data?
The data was imprinted in pattern, that pattern was like a sand painting. Degaussing is like the wind.

The data essentially melted into a larger dynamic state wave that dissipated into heat, sound, and a residual magnetic imprint from which no delicate nuance can be derived.
Eliminating or reducing the magnetic presence then. If the first then do the laws of thermodynamics still hold?
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Re: Memory and erasure of hard drives

Post by crochambeau »

Indeterminacy wrote: Thu Jun 16, 2022 4:13 am Eliminating or reducing the magnetic presence then. If the first then do the laws of thermodynamics still hold?
Not eliminating, disrupting the pattern previously woven. It's like a glass full of water, upending the glass can make the water undrinkable, yet the water has not been destroyed.

Particles charged magnetically are a polarized condition. It is the majority alignment of particle charges that sums to a magnetic state. The substrates that carry the magnetic state are engineered of materials that do not exhibit an inherent preference of one state over another - otherwise any data entrained within the magnetic pattern would erode as stresses to a magnetic preference would relax.

Imagine the particles as millions of ping pong balls floating within a wire grid on the surface of still water. Each ping pong ball is painted, one half black, one half white. Standard write operations involve swinging someone out over the water who is able to reach down and rotate the floating ball to present either the white or black face. Reading is simply scanning the states.

Now, degaussing raises and lowers the level of the water in a violent enough manner that the positioned states of all of the balls has been fucked with.

Nothing has been destroyed except the orientation of the fields, the pattern, the information.
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