I haven't checked other parts, but if they are like that it would be more a very elaborate demo than something actually usable.
Still impressive even for a demo.
Now for the rest of my life, I will always have something to hack on. :)
This is such an inspiring and humbling sentiment!
Thank you for all your hard work on this impressive project.
Depending of the definition of "usable." It's surely usable for anybody who wants to learn the basic ideas.
It's written from the scratch, and just a small part of the whole system.
To get the idea how the networking stack were introduced to the famous systems see, for example, how may people were involved in creating the Windows networking stack with TCP/IP, at the moment the already had other kinds of networking, and as Berkeley sockets already existed for years:
"The idea for Windows Sockets was first proposed by JSB's Martin Hall at a Birds Of a Feather session at Fall Interop in San Jose in September 1991. Around 40 companies were formative members of the Windows Sockets group. Representatives from these companies gathered in Seattle in December 1991 to debate and resolve the basis of Windows Sockets. Considerable effort between then and January 1993, which involved a substantial amount of Internet-based email discussion, together with several meetings and 2 interoperability testing sessions (WinSockathons) led to version 1.1 of the Windows Sockets specification which is the definitive reference point for Windows Sockets today. WinSockathon II proved that Windows Sockets 1.1 is a viable standard for application/network implementation interoperability."
On 16 bit platforms, we needed to buy it as additional software package.
I totally agree with the author to do the minimum otherwise just one part can delay all.
"Comparing TCP/IP products for PCs"
"PathWay Access 3.2 (The Wollongong Group)" ... "The PathWay product installed more easily than all the rest. We found it amusing that Wollongong managed to squeeze its software into five disks while others needed up to 15 disks for essentially the same software"
Rapidly MVP as much as you can do you have something usable. Then go back and refine the warts as and when they become a nuisance.