EtherDFS is an 'installable filesystem' TSR for DOS. It maps a drive from a remote computer (typically Linux-based) to a local drive letter, using raw ethernet frames to communicate. For years, I was using LapLink to transfer files between my various "retro" computers. It works, yes, but it's also annoyingly slow and requires constant attention. One day I thought, "Wouldn't it be amazing if all my DOS PCs could share a common network drive, similarly to how NFS operates in the *nix world?". This day EtherDFS was born. I clearly didn't invent anything - the concept has been around almost as long as the first IBM PC, and several commercial products addressed that need in the past. I am not aware, however, of any free and open-source solution. Besides, all the commercial solutions I know require to set up a pretty complex network
environment first, while EtherDFS doesn't need anything more than just a packet driver.

EtherDFS is the "client" part, ie. the TSR running on the client DOS computer. The client requires an EtherSRV instance to communicate with. Currently, an implementation of EtherSRV exists only for Linux (ethersrv-linux). Since EtherDFS runs over raw ethernet, it doesn't need any TCP/IP stack. It only requires a working packet driver. The catch of using raw ethernet frames is that EtherDFS is, by design, unable to communicate outside of a single LAN. In some context this might actually be a strenght, you don't need to worry that your EtherDFS transfer will somehow leak outside your LAN - it's simply not possible.