Re: Rust? (and a wordsmithing question) (was: Re: Embarrassing security bug in systemd)
On Monday, December 11, 2017 09:41:45 AM Darac Marjal wrote:
> On Mon, Dec 11, 2017 at 09:16:35AM -0500, rhkramer@gmail.com wrote:
> > From the Wikipedia article on "Magnetic storage":
> > https://en.wikipedia.org/wiki/Magnetic_storage#Design
> > "For reliable storage of data, the recording material needs to resist
> > self-demagnetisation, which occurs when the magnetic domains repel
> > each other. Magnetic domains written too densely together to a weakly
> > magnetisable material will degrade over time due to rotation of the
> > [1]magnetic moment one or more domains to cancel out these forces. The
> > domains rotate sideways to a halfway position that weakens the
> > readability of the domain and relieves the magnetic stresses. Older
> > hard disk drives used [2]iron(III) oxide as the magnetic material, but
> > current disks use a [3]cobalt-based alloy.[4][1]"
> > I have trouble understanding that 2nd sentence: "Magnetic domains
> > written too densely together to a weakly magnetisable material will
> > degrade over time due to rotation of the [5]magnetic moment one or
> > more domains to cancel out these forces." and would like to rewrite it
> > to be more clear--I'll make an attempt below--suggestions are welcome:
> > "Magnetic domains written too densely together to a weakly magnetisable
> > material will degrade over time--the magnetic forces which impact the
> > disk during rotation will cause one or more of the tiny magnetic
> > domains to rotate to (partialy) cancel out the intended magnetization
> > (which stores the data)."
>
> Be careful. As I understand it, the force which causes the
> demagnetisation has little, if anything, to do with rotation of the
> platter. Rather, the problem lies in the fact that, let's say you have
> 1-0-1 stored on the disk, those two 1s provide a force which "pulls" on
> the 0 until it looks more like a 1 than a 0.
Ok--thanks for the reply. I guess I'll wait until I acquire more information
/ understanding (perhaps by osmosis--i.e., probably passively rather than by
active (re-)search).
I guess part of my (the?) problem is the word rotation in the first iteration
of the sentence--I assumed that was rotation of the disk (in things like (1)
the magnetic fields associated with the read (and write) heads, and (2) maybe
the earth's magnetic field.
Maybe the interpretation of the word rotation is more like you imply--rotation
of the magnetic field of the (for example) 0 in response to the two adjacent
1s.
I guess the more I re-read that sentence, the more I tend to think that your
interpretation is the correct one.
Any hints appreciated.
> > I'll probably also replace "too densely together" with either "too
> > close together" or "too densely".
> >
> >
> >
> > Maybe I've combined too much of the third sentence into the second
> > sentence and it might stand rewriting as well.
> >
> >
> >
> >References
> >
> > Visible links
> > 1. https://en.wikipedia.org/wiki/Magnetic_moment
> > 2. https://en.wikipedia.org/wiki/Iron%28III%29_oxide
> > 3. https://en.wikipedia.org/wiki/Cobalt
> > 4. https://en.wikipedia.org/wiki/Magnetic_storage#cite_note-AutoMK-13-1
> > 5. https://en.wikipedia.org/wiki/Magnetic_moment
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