On Tue, 2002-10-29 at 18:15, John Orr wrote: > Personally, I think he is full of... hot air. > > Bits are either "on" or "off", "1" or "0". If you change that pattern (i.e. write >over the same data area with a different sequence of bits), then the previous state >of that field would not be determinable. Granted, there may be some residual >magnetic field left on a particular area that is now "0" that had been "1", but the >converse would not be true. There would be no residual field to read on an area that >is now "1" that had been "0".
Apologies if I'm talking out of my nether regions, but (looking at it superficicially) I wouldn't have thought that storing/reading a magnetic impulse would be quite as clear cut as zeroes and ones. I'd have thought that some fuzzy interpretation was required ie, x to y is the normal range taken to represent a zero, a to b to represent a one. In this case, it's entirely possible that, for a known drive with known parameters, it *may* be possible to say "yes, that's a one but it's slightly higher than normal so it may have been a one previously as well". This is, of course, nothing more than utter speculation from someone who knows nothing about it ;-) J -- John Dow <[EMAIL PROTECTED]> http://www.nelefa.org 33 Shines
