Re: TDS3000B USB floppy emulator


On-topic:  My own experience with 720K 3.5 inch disks is entirely with a
Toshiba T1000 laptop computer (running DOS 2.x) that I think I purchased
around 1988.  The T1000 had/has a single 720K 3.5 inch drive, and while
it worked fine (read/write/format) with any 3.5 inch disk labeled as
"DD" (720K), it was totally unusable with any floppy labeled as "HD"
(1.44M). It would not even format an brand-new unformatted HD floppy as
a 720K disk, which surprised me.  I still have the T1000 (stored away
somewhere in a box), along with a bunch of DD 720K 3.5 inch disks.  When
I last used the T1000 (early 1990's) the DD (720K) disks had become
pretty much unobtanium; I kept all the 720K disks that I had when I
subsequently "retired" the T1000 because I figured the T1000 would be
unusable without them.  I seem to also remember that reading or writing
any 720K disk on other computer(s) with a HD (1.44M) disk drive was
"iffy" at best.

Off-topic: if anyone has managed to retrofit a T1000 with a HD drive and
is willing to share the info with me as to how it went, please contact
me directly (_not_ thru the Tekscopes user group) to share the info, at
<mdinolfo> <at> <erols> <dot> <com>.

Mike Dinolfo N4MWP

On 2/3/20 1:14 PM, John Ferguson via Groups.Io wrote:

This may not be that illuminating, but my memory from the time these
disks were in daily use was that there were drive differences as well
as disk differences and that it was not at all certain that a
particular disk could be read in nay drive.  Their were different
coating formulations, ED, DD, and HD.  I suspect that the DD (Double
Density) forumulation worked at 720 KB and the HD at something like
1.4 MByte.

I'm pretty sure that an HD disk will not work on a DDdrive for example.

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