> Thanks so much for that - I was working on figuring out how to get ghidra to 
> run (It refuses to see my Java version).   Minecraft and eclipse here work 
> just fine, so java is ok...It will be some stupid path variable that is 
> conflicting with what it expects

No problem! Ghidra uses the Java development kit (JDK), not the regular release 
of Java. I ran into the same dilemma when I installed it for the first time.

There are definitely some clever design choices and programming tricks put into 
the DVI.

That’s interesting that you bring up the potential for the floppy drive to be 
double sided. The DVI even goes as far as having a hardware register 
implemented for side select, but so far I’ve only seen side 0 be selected by 
the software. This is the reason I started digging into all of this. I’d like 
to patch the boot disk to include modified routines for accessing both sides of 
a disk (after the drive has been swapped for a DS one, of course). 

You can see from the disassembly, I’m only as far as the system grabbing the 
IPL and running that to grab DOS (12 sectors of data from track 1 sectors 
2-14). The IPL is putting the data copied from those 12 sectors into RAM1 (bank 
switched in place of ROM) starting at address 0x0000. After it’s loaded, the 
IPL jumps to 0x0000 to run DOS. 

I still need to copy and paste the 12 sectors of DOS from the files extracted 
from the disk image by Steve Adolph into RAM1 in Ghidra and tell it to 
disassemble that code next. 

I also need go back and fix a bunch of assumptions in labels and comments. Some 
right, some wrong, some still needing further evaluation. 

Royce

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