Interesting piece of history.

This reminds of a quixotic quest I undertook once - implementing enough of a SLIP and TCP/IP stack to send mail with SMTP and retrieve it with POP3, all in PC BASIC (the kind that still required line numbers).

Amongst other problems, it wouldn't work properly (dropped characters) at anything faster than 9,600 baud, and on an original PC needed to go a bit slower than that; computing things like checksums was exceedingly painful; there wasn't enough RAM (it was limited to 64K for program plus data, which in practical terms meant a PC with at least 96K of RAM); it would have to drop the connection if it shelled out to an external editor. But it did work.