Ok then. Sorry, if my response discouraged you. 🙁
But I also have a good news, the missing option for B: is a pure BIOS limitation and can be patched.
The average on-board floppy controller is a derivative of the good ol' Shugart interface and can drive a second (or third) floppy with no problem.
The reason I said it's complex, is because it depends on the type of computer system you have, so theres's no general answer.
As far as I know, there are several ways to add more floppies to a PC..
For example, the orignal PC 5150 had the ability to use up to 4 drives (set via jumpers).
I don't know why, maybe because it did not support fixed disk drives and thus the letters "C" and "D" were not assigned.
If we think about it and the fact it also came with an cassette port, this idea isn't too implausible.
On the PC/AT (and its successors) however, things are a bit different.
The AT-style BIOS reserves the "C:" drive for a hard disk and it's CMOS utility doesn't have the ability to setup a third or fourth floppy drive.
This is where driver.sys can help. If you made a special floppy cable and load this driver, you can setup a logical drive and assign it to a free drive letter you wish (like "X" or "Y").
However, I don't know if this works for low-level routines used by games or copy utilities.
I don't know for sure, but this driver.sys trick may also work with a second floppy controller.
If one of those old 8bit dinosaurs had jumpers, you could set it to another port address.
Or if you can get a floppy based tape controller, you can use that aswell.
Then, you only need to patch driver.sys to look out for that non-standard port (a hex editor is all you need).
But this is pure speculation, maybe I'm wrong here. I know a bit about CP/M machines, but my knowledge about PC/XT class machines is next to zero.
And there's also the PS/2 line, which uses a different kind of BIOS.
I have no idea whether or not it supports more than two floppy drives, but I've seen a lot of external drives for it (possibly SCSI based ?)
After all, the easiest way for you is probably to use one of those 4-drive floppy controllers with their own BIOS.
They sometimes show up on eBay, but I've never got one myself.
Here's a bit of something to read. Maybe it can help you further.
More Than Two Floppy Drives
The Floppy Interface in Waveterm A und B
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