[vram22]

I once corresponded with someone who wrote his own working TCP/IP stack for his own home PC, an IBM PC Jr.

See Mike's PCJr page near end of this post:

http://jugad2.blogspot.in/2012/09/lissajous-hippo.html

[vram22]

Update: Visited his page again. He has now even created a web server for the PCJr and ran his site on it for a while.