MAMEWorld Forums - News - Re: Star Rider emulation progress

> > I haven't followed the Apple II progress in MESS other than reading RB's hardware
> > card support over the past year. It does appear the software list (hash file) is up
> > and running so your preserved floppy diskette images should be able to drop in.
> > Whether images run in MESS is another thing....in case apple2.c file might need to
> be
> > updated again to handle diskette images (copy protection etc.)
>
> Our ability to currently run a properly dumped protected original is sketchy at the
> moment. I have long-suffering plans to rewrite all the Apple II floppy stuff, but my
> eyes glaze over every time I look at OG's modern floppy stuff. I just don't speak PLL
> ;-)

Shouldn't be a problem, there's no PLL in the apple 2 :-P

I'm still working on the floppy doc, it's just a bad time of the year, work-wise. There are two problems with the apple 2. First is how to handle the state machine in a predict/commit fashion. But in practice that should not be a problem, I think. The second, more annoying, is that the nibble format, the one used for protections, is a pile of crap.

Theorically the nibble format is a direct image of what's on the floppy. In practice you can't fit it in a floppy. A floppy track is build of sectors with non-data zones called gaps separating them, protecting them from each-other. Wozniak, being the insane genius we all know, decided to automatically size the gaps to make them maximal for the real clock rate and floppy rotation speed you have. So formatting goes "write the track with way too big gaps, check if the first sector got overwritten, since it did reduce the gap size and try again until it works". The first iteration of that loop writes iirc around 1.3 times the normal track size.

Guess what the nibble format includes? You got it, it's the version with the way too big gaps. So you have to remove part of the gap data (they are ffs, easy to see, theorically) so that it fits, but since it's a format for protections you have to be sure what was there and what was added by the stupid format. That currently stopped me.

OG.