[Coco] Re: Floppy contoler Q

[farna at att.net]

Don't forget the DECB only has four drive numbers. So with it you're limited to four single sided drives. This can be two double sided drives with the side select making them four single sided, or  four "real" single sided drives, or a combo of the above. I had three drives attached to my computer -- ADOS read the two double sided drives as four single sided floppies, and a 3.5" 720K drive was connected for OS-9 use. 

I realize this discussion was really geared toward OS-9, which is almost unlimited as far as number of drives. The only limitations are the controller and memory to load drivers. With the Tandy controller the practical limit is three double sided floppies. I'm suspecting that Art is correct -- a fourth single sided drive could conceivably be wired in, but I don't see a practical reason to do so. Of course with some logic circuits added to the drive and side select lines a lot more floppies could be connected -- just manipulate the bits in the correct combination with the drivers. I think that falls under "if there's a will there's a way" though -- is there a practical reason to have 16 floppies connected when you can only read/write to one at a time? Unless you want to boost the signal and write to several at a time for copying purposes, I'd think not. 

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