Posted by: "Lou Judson"
> Aha, 3.5 Magneto-Optical discs. I haven't seen one since 1991 (or was
> that a Bernolli?), can you elaborate, even just a link for this
> ignorant one?
Bernolli was more or less just a giant floppy disk, magnetic media.
The 3.5" MO disks have evolved since you last looked at them. They
started as 128meg and now I have sitting right here a 2.3 gig MO drive.
That drive reads and writes all sizes of the disks. There may even be
bigger disks than that. I have a number of drives here, even ones for
portable use plugged into a laptop via USB that are very small.
The disk itself looks from the outside like a double thick floppy disk,
hard protective case with a metal shutter. You can use storage for
floppies for them. Of course inside is the Magneto-Optical media which
is not at all like the floppy.
The primary users of these have been banks, people backing up the
primary copies of data long term, that sort of thing. I've been using
them since they were first introduced. About the time everyone was
buying zip drives as they were cheap I was buying MO because it was
reliable. Some of the first disks I had still have the original
recording on them.
The coatings on the 3.5's are a little more durable than those on the
minidiscs, and the mechanical wear on the backside is less. Thus they
end up rated over 100 years. I know I've never had a disk fail or wear
out. The way the disks are written has changed too. The biggest change
was when they went to a one pass write. Earlier disks had a erase pass
then a write pass, but current technology is one pass to erase and write
at the same time. Note that the light used is different from minidiscs too.
In the US Fujitsu has been the primary supplier of drives for consumer
use. In Japan and other countries there are more suppliers.
I mostly use 640 meg versions now. Primarily as they are the most common
larger size to turn up on Ebay, which is a pretty good way to get the
disks cheap. Even used disks are fine due to their extreme durability
and often that's what turns up on ebay. The final death of a company may
be when their master backup disks are sold off on ebay and get erased
and reused.
Walt
|