SORT by INDEX HOLE POSITION!
On Wed, 17 Sep 2003, Nico de Jong wrote:
> > >A hint : sort the floppies according to density. I would be rather p.....
> > >if I bought a stack of 20 floppies, believing they were DSDD, and I got
> > >some SSSD ones.
> > Is there a way to tell visually if they are DS vs SS? Not all the
> > floppies have their original factory labels on them any more, and I know
> > there are some of each.
> I just checked some of mine, and there is not really "conclusive evidence".
> On top of that, some SSSD floppies were rejected DSDD's. The good thing
> is, that I've never seen a double sided that couldnt be used as single
> sided. The story behind this is rather remarkable: when we talk about
> 3740 floppies (i.e. IBM labelled), the f?rst track is always written as
> single-side single-density, as some drives and/or systems can detect the
> disk format and/or re-assign defective tracks. So, selling "unknowns" as
> SSSD should be safe, and if they get a DSSD or DSDD (yes, they exist!),
> they were just lucky.
ALMOST.
There is no visible difference between SD single density v DD Double
density.
But, if you take a look at SS Single sided v DS double sided, the index
hole is in a different place!
Most double sided drives have BOTH sets of index holes, and therefore can
format a DS disk as single sided, if so requested.
BUT, some single sided drives can NOT format a disk that only has the DS
index holes.
That is further complicated by the fact that after a disk has been
formatted (or reformatted after you bulk-erase them) that the index hole
can then be ignored, permitting using disks with index holes that don't
match the drive! (after they were formatted on a different drive)
Therefore, sort them by the index hole position, and you will have
successfully identified which ones can be formatted as SS v DS in the
appropriate drives.
--
Fred Cisin cisin_at_xenosoft.com
XenoSoft http://www.xenosoft.com
PO Box 1236 (510) 558-9366
Berkeley, CA 94701-1236
Received on Wed Sep 17 2003 - 13:22:00 BST