Re: [hatari-devel] Hard drive emulation question

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 29/11/2024 à 10:02, Laurent Sallafranque a écrit :
> Hi Hatarians,
>
> I've got a little question about hard drive emulation under Hatari.
>
> When I code a game or a demo which loads data from the hard drive, the 
> loading speeds varies a lot between my Linux fast PC and my real falcon 
> compact  flash memory card (and I guess it would also vary with a real 
> mechanical hard drive).
>
> Under hatari, it loads nearly instantly.
> Under real falcon, there's a few ms to seconds delay before loading is 
> finished.
>
> Would it be possible to introduce a "disk timing" parameter in the 
> Hatari GUI parameters that would allow to "set virtually" a hard drive 
> timing access ?
>
> There's no urge in this request, it's just for emulating closer "real 
> hardware experience".
>
> Regards
> Laurent

Hi

I made some similar changes for the FDC some times ago.
commit 9dc550b0f2fb3 from 3/10/2021 adds a 4 cycles delay per word 
transferred in the DMA FIFO.

The same could be applied to HD, but there're several HD emulations :
 - gemdos mode (mapped to the unerlying filesystem)
 - acsi and scsi emulation on a disk file image

each one would require a specific patch

As gemdos HD mode is not a "real" HW feature, maybe the delays should be 
added only when using acsi/scsi mode.

Which one are you using for your tests ?

Nicolas