Not the OP, but I guess the power of Raspberry Pi is that everyone already has one - really useful if you want to do something in a hurry without anything extra. I've used a Pi as an emergency programmer on multiple occasions, as an SPI flash burner, as an SWD debugger, as an AVR programmer. You can even use the Pi as an USB-FDD bootdisk or emulate an IDE driver via its parallel interface.
I guess it doesn't have to be a pi. The idea would be that the pi would connect to your network and provide the floppy drive into an older system. Any system on the network could command the pi to mount the floppy image to the connected device.
Basically I don't want to have to be constantly moving a usb disk around.
Ultimately, the pi is unsuitable for deterministic behavior, and Linux is unsuitable for the kind of realtime needed to sample from a floppy directly.
Don't get me wrong: It would be possible to do it, but it would be theoretically not reliable, even if it felt reliable. You'd also need some sort of glue in between, as floppy drives signal at 5v and the rpi isn't 5v tolerant.
Therefore, you could connect the pi to the stm32, rather than directly run the floppy drive from the pi.
My guess is that he has one already, so why buy new kit if unneeded? I was excited about Pi1541 as I have a C128D that needs more of a life than one C64 Flight Simulator II disc I have handy, but it only runs on more recent models than my 1B.
Not the OP, but I guess the power of Raspberry Pi is that everyone already has one - really useful if you want to do something in a hurry without anything extra. I've used a Pi as an emergency programmer on multiple occasions, as an SPI flash burner, as an SWD debugger, as an AVR programmer. You can even use the Pi as an USB-FDD bootdisk or emulate an IDE driver via its parallel interface.