The internal hard drive is drive 4. The MII boot rom looks for a drive 4 and will boot from there before prompting for a floppy to boot from in drive 0.
That's been going on forever. Does counting start at 0 or 1. If your drive is numbered DS1 through 4, subtract 1 in Tandyland.To further add to the confusion, I'm finding that floppy drive manufacturers and Tandy didn't agree upon whether to call the drive IDs DS0..DS3 vs. DS1..DS4.
Sorry, all of this is stuff I take for granted. I was working on these machines when they were new...
For the floppy drives on the model 6000 (and 16b) - DS0 is not available on the external interface. DS1 is not by default in a 2 floppy drive system, it is if the system originally shipped with an internal hard drive.
Floppy and Hard drive selects are independent. Something so obvious for those from the trenches, but so easy to get confused about today.
HD DS0 and FD DS0 are not related at all.
So you are saying that the external drive must use ds1 if jumper is shorted on motherboard? I have a 6000HD. Please clarify if you can. Sorry for all the dumb questions. I feel like a total newbie on these machines. Even though I had a model I back in 1978.
- The boot floppy drive, DS0, is always on the internal floppy cable.
- Floppy drive DS1 can be either on the internal floppy cable (jumper E40/E41 removed) or on the external floppy cable (jumper E40/E41 installed). Since you have a 6000HD, I think it makes sense for you to install jumper E40/E41, allowing up to three drives to be on the external cable.
- Floppy drives DS2 and DS3 are always on the external floppy cable.
- In all cases, each individual drive needs to be jumpered to respond to the desired drive select signal.
Does this help?