First 3.5 inch FDD [WAS: RE: Prototype IBM DemiDiskette drive]

[Eric Smith]

On Thu, Aug 23, 2018 at 12:43 PM, Tom Gardner via cctalk <
cctalk at classiccmp.org> wrote:

> Well it all depends upon what u mean by "first"
>
> The Sony drive and cartridge were not compatible in many ways with what
> became the physical, magnetic and electrical interface standards for the
> 3.5-inch drive and cartridge.  The standards came out of the "Microfloppy
> Industry Committee" (Google it with quotes) organized by Shugart Corp.
> Either Shugart or Tandon was the first to ship drives compatible to the
> standard.  Tandon probably did the first such cartridge.
>
> The original Sony drive and cartridge died out and Sony didn't come out
> with
> a compatible set until well after Shugart and Tandon.  The early adopters
> of
> the Sony design like HP then changed to the industry standard design.
>

AFAICT, the only difference was that the pre-standard Sony 3.5-inch
diskettes had a manually operated shutter. The manual shutter and automatic
shutter 3.5-inch diskettes are interchangeable with some care.

For a while, diskettes were sold that had the automatic shutter, but also
had a way the user could latch the shutter open, so that they could be used
in early drives that didn't have the pin to open the automatic shutter.

I only ever saw the manual-shutter drives in Sony and HP equipment, though
I wouldn't be surprised if there were some other uses.