Re: [hatari-devel] HD floppy timing

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

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.