Work on this is now pretty much complete for the time being. It turned out to be much easier than I anticipated. Write access now works; directory structure and time stamps don’t. I’m not too bothered about a directory structure right now, as the root directory can hold 512 entries – in any case I don’t intend FAT to be the long-term file system, so I don’t want to do more than the necessary minimum of work on it. Time stamping would be of little use until some form of time-of-day clock is implemented (shouldn’t be too difficult). I’ll now work on documenting and publishing this latest version.
What next? Current work has shown up a problem when running under QEMU; sometimes it needs two or three attempts before the system runs. These problems don’t occur under SimNow, so I’m guessing it’s a question of uninitialized variables. Other than that, I think that I’ll look at implementing a few simple commands – cat, ls, cp, that sort of thing. Another thing that I think I may look at is changing the memory map to give more available memory to the various parts of the system.