[rescue] nuking from orbit

[Mike Free]

    The problem with this argument is, that 10 or 20 molecule wide data
stripe left my the misaligned write head, _should be_ enough to decipher
whatever you have on that disk. the coding of the information, no matter how
analog the media gets, is still analog... a .1 micron wide byte is still a
byte, and is still data to be read. These stripes will also more likely than
not be obliterated during (cover my ass statement) MOST use for several
reasons, that the timing data is not always the same opening possibilities
at the beginning or end of the written byte for data to survive, and that if
the computer is used immediately after startup, there will be an
inaccessible data stripe remaining towards the inner circumference of the
cylinder due to the expansion of the metal platter during warmup. There's
also a factor for gaussian bleed, where the longer the data stays on a drive
the more it influences into the depth of the recording media on some media
types, and lately written data in that case would not penetrate the media as
deeply, and all it would take to retrieve older data is to "read deeper"
into the media either electrically, or physically.... I'm certain there are
even more ways to retrieve magnetic media than what I can think of in my
tired state....

Mike Free

P.S. there is another way i just thought of, i'm not terribly sure about it,
but thinking about the manner in which an electromagnet functions it would
have a non-linear field......towards the edges of that field in the data
bit, the particles would not be so influenced as in the middle... data
recording being digital in nature means that each individual bit is assigned
a particular "spot" on the disk. What this means is, you can read the
percentage of opposing bits in the edge of the field affected area and
statistically show whether or not the previously assigned bit was the same
or different from the currently assigned bit. Maybe I should do this for a
living.....

> > >left on the disk.  Try to tell John Voight from Christopher Walken
> through a
> > >picture of Anna Kournikova's backside.
> >
> > Your error is in assuming that the bits that will be changed will be
> > exactly the same.
> > Do you think that just one or two molecules is enough for the head to
pick
> > up the bit?  No, there are many many molecules that are charged, even
with
> > today's high bit densities.
> > Do you think that the head, as it is flying over the surface, stays in
> > EXACTLY EXACTLY the same location each time?  No, it does vary, by a
small
> > amount to be sure, but enough to figure out what is going on.
> all these reasons are why after 27 write cycles, each with a
MICROSCOPICALLY
> different head alignment, the whole zone will be OBLITERATED.
>
> >
> > Do you think that you are dealing with an entirely digital process when
> > dealing with a hard drive?  No, you are not.  Not every molecule is
> charged
> > in the area of a particular bit.
> No, of course not, actually, the "charge" you speak of requires Multiple
> Molecules in the first place.  And no, ti is not an entirely digital
> process,  it is a digital process made up of fine grained analog values.
> All computer systems we use today are...  even the switching done at the
> transistor level in a CPU is analog if you look at it close enough.
> My point is, even if you can erase only 90% of the blackboard, after I
fill
> and erase it 10 times, you will never be able to make out the 0.0005%
image
> of the first write among the 10% image of the last 100% coverage, stepping
> bit, test pattern write.  it's analogous to:
>
> filling a blackboard with text,
> erasing it, leaving a 10% image
>     let I=10:for 1 to I do;
>         scribbling it over with 100% coverage with chalk
>         and erasing it again
>     loop:attempt to read text
> end
>
>
>
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