Allow SAVE/LOAD to disk

[unbibium]

CBM disk drives took responsibility for the filesystem. Reading and writing files were simple serial transactions between the computer and the drive. This is why you could turn on the machine and just type LOAD"*",8,1 and it would load the first file on disk.

Atari disk drives had a microprocessor, but it was limited to reading and writing by sector. Atari computers had disk routines, but they were limited to reading the first few sectors from disk and loading enough code to boot the rest of the disk. To access a filesystem, a DOS had to be loaded into memory. There were multiple filesystems, and not all were compatible with each other.

With these two competing paradigms in play, designing a way to save to disk is going to be difficult.

Options as I see them:

• create some serial adapter to connect real CBM disk drives, and adapt CBM's I/O directly
• adapt Atari's sector-based I/O protocol, AND write a filesystem around it, to use Atari disk drives.

[polluks]

You don't have to write a filesystem from scratch, use a game DOS like https://atariwiki.org/wiki/Wiki.jsp?page=XBIOS.