Re: [hatari-devel] HD floppy timing

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 31/05/2016 à 10:38, Nicolas Pomarède a écrit :
> Le 31/05/2016 00:28, Roger Burrows a écrit :
> > On 30 May 2016 at 17:45, Nicolas Pomarède wrote:
> > > I never really checked the accuracy of HD/ED format, since no program is
> > > known to depend on this (it's not the case for DD where game protections
> > > expect very precise timing for gap, read sector and so on).
> > >
> > > Basically, DD timings to transfer a byte from floppy are divided by 2
> > > for HD and divided by 4 for ED.
> > >
> > > It's quite possible this doesn't give the same values as real HW :)
> > I think I can guess the problem: the emulated HD drives are spinning
> > at twice
> > the speed of a DD, so a sector miss (extra revolution) takes 100 msec
> > when it
> > should take 200msec.  Not a problem for games, but it does make Hatari
> > less
> > accurate as a tool.
>
> I will have a look, it's possible HD and ED disks don't have a 300 RPM
> in Hatari at the moment (which they should) and this would explain the
> problem.

Hi

when testing with the attached FLRPMM.PRG, I get 600 RPM for DD, HD and 
ED floppies if use Hatari with STF mode running at 16 MHz ; this should 
On the other end, DD, HD and ED floppies all report 300 RPM with STF at 
8 MHz.

In your case in Falcon mode, do you see 100 msec for a sector miss only 
when using ED floppy, or is it also the case for DD and HD floppies ?

My guess is that RPM is wrongly affected by cpu speed multiplier, which 
shouldn't be the case.

Nicolas