Re: [hatari-devel] New stream by Cybernetics - write floppy disk issue

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 15/08/2014 19:04, Eero Tamminen a écrit :
> Hi,
>
> On perjantai 15 elokuu 2014, Konador, Cyprian wrote:
> > That demo contains WRITER.PRG, which fails when it tries to write
> > NEWSTREM.IMG file onto floppy disk.
> > http://www.pouet.net/prod.php?which=14458
> >
> > I'm not sure but maybe this issue is caused by mentioned by you lack of
> > FDC type III command "write track" support.
>
> Yes, as Hatari says:
> FDC type III command 'write track' is not supported with ST/MSA files
>
> Use STX image file instead.

Write track is not supported. Strange idea to distribute the demo this 
way, this IMG format looks like a .ST file (dump of all sectors) but 
with a small 8 byte header (839688 instead of 839680 bytes for a 82 
tracks, 10 sectors floppy)

> As to writing tracks to ST image...  Disk image geometry obviously
> needs to match what the writer is trying/going to put put to the disk
> (so that it doesn't try to overwrite past image size), but if
> that is true, I think Hatari could just extract sector contents
> from track data and write them to places that would correspond
> to the them with current disk geometry.

I already thought about this, but in the end, this will rarely work ; 
program using write track have often good reason to do so, just keeping 
the sector data will often not be enough (it would only work when write 
track is used to format the track and some write sectors will be sent after)

All in all, I think I might add some kind of MFM disk support one day, 
to store the raw data as the WD1772 would use it.

Nicolas