Re: [hatari-devel] Re: Hatari floppy drive detection with EmuTOS

[David Savinkoff <dsavnkff@xxxxxxxxx>]

----- David Savinkoff <dsavnkff@xxxxxxxxx> wrote:
> ----- Nicolas Pomarède wrote:
> > Le 16/01/2014 01:09, David Savinkoff a écrit :
> > >> Note that to detect index pulses you normally need one drive, but also
> > >> one floppy in it.
> > >
> > > On 3.5" drives, the index is in the drive. Thus, no floppy is required.
> > >
> > >
> > 
> > Are you sure of that, do you have some tech doc on this, datasheet for a 
> > particular model ?
> > 
> > This would explain a lot of things, but I think I read on the contrary 
> > that many drives (not 3.5'') had internal index, while the 3.5'' relied 
> > on the one present on the floppy (and as far as I understand their code, 
> > the IPF library that emulates the WD1772 also assumes index on the floppy)
> > 
> > Nicolas
> > 
> I recently disassembled my SF354 and also a modern Samsung and also saw
> a picture on atari-forum. None require a floppy inserted because the sensor
> is beside the motor. It doubt any 3.5" drives rely on a floppy disk to be
> present.
> 
> David
> 

I looked at a floppy disk drive specification and found that, on that drive,
index pulses were logically inhibited when the 3.5" floppy was ejected.

Note that a 3.5" floppy disk is locked to the floppy drive spindle in one
position only (unlike 5.25" disks).

So I guess you cannot expect index pulses from a 3.5" drive when there
is no floppy case present.

David