Re: Information & Power /Alexandria library
Michael S. Lorrey (mike@lorrey.com)
Tue, 04 May 1999 09:08:09 -0400
Ron Kean wrote:
> On Mon, 03 May 1999 14:56:33 -0400 "Michael S. Lorrey" <mike@lorrey.com>
> writes:
> >
>
> >Tapes do not rely on chemical reactions, but on magnetic fields.
> >Granted, if the medium oxidizes, the fields are lost. Proper storage
> >prevents oxidization. Of course the lowest quality tapes will degrade
> >easier. Iron degrades far faster than, say, platinum, silver, or gold
> >tapes.
> >
> >
> >
>
> Is not magnetic tape already oxidized, as the material which carries the
> magnetic domains is iron oxide? Would not tapes made of platinum,
> silver, or gold fail to work, as those materials are not ferromagnetic?
I should have said further oxidization. Some iron oxides are ferromagnetic, others are not. I'm not sure the proper molecule for the ferromagentic types, but once extra oxygen gets added on, its toast. The precious metals apparently are alloyed or compounded with the ferrous oxide and aids stability. I'll check on this, but I do know that while standard old tapes will usually develop bad blocks near the beginning of the tapes (closest to the outside environment), the gold, platinum, and silver tapes tend to remain error free unless they've been misused. They also read and write much faster (fewer rewrites) than standard tapes. The other day I used a silver tape dated 1963 and it read and wrote cleanly.
Mike Lorrey