"Mayayana" on Fri, 1 Dec 2017 19:27:40 -0500
typed in alt.windows7.general the following:
"Char Jackson" wrote

| Mayayana mentioned grooves in plastic within the context of backing up
| data to DVD. Obviously, there are no grooves... ;-)
|

My understanding is that the writer cuts grooves
at various depths underneath the surface as a way
to record data. Is that wrong? In any case, it cuts
some kind of marks in plastic. It's not just magnetic
storage.

Close, sort of. The laser burns a "pit" which on read gets
interpreted as "zero" - everything else is a one.

"Magnetic media" (floppies, tapes, wire if you go back far enough)
are all subject to fluctuating magnetic fields, not to mention "decay"
in the magnetic signal.
CD/DVDs lack that property - but have others (delaminating discs
being the big one).



--
pyotr filipivich
Next month's Panel: Graft - Boon or blessing?