I already have a NAS but i’m looking for a way to transfer files over USB so I can share data on the fly from a mounted folder.
I’ve done OTG based networking with a Pi Zero and I could probably get OTG mass storage working but it requires a USB chip compatible with gadget mode and the appropriate modules turned on in the kernel. Support seems to be the exception rather than the rule and i’d like the freedom to pick any hardware.
One challenge that I can think of is the power that is pumped through the USB. I’m guessing that negating that power is probably the role of the gadget mode chip. Is Ethernet a possibility? You could transpose the TX and RX cables on a diy CATx cable (or cut the power cable – #1 pin – on the USB cable? Maybe?). I’d do lots of research before I tried it on “keeper” hardware.
The Startech does do power isolation, i’ve just never used one so I have no idea how it works and I can’t find anyone using Linux who has.
I’ve done LAN to LAN with a Raspi 2 but not with a special LAN cable, I used it to drive a 3rd monitor for my laptop using tigervnc. A special LAN cable sounds interesting though I wouldn’t have the “on-the-fly” mass storage aspect.
The cat 5 cable is a crossover. It essentially does the job of a switch or hub in the actual cable. We used to make them to hook 2 computers together in a small office that way we didn’t have to spend $ on a hub or switch.
Heavily dependent on your USB ports available but i have used two cheap usb Ethernet adapters for this with good success. Close to gigabit Ethernet speeds at least (with usb 3.x — much less if you’re limited to usb 2 but still works at least)