KA9Q Mirror

Mirror directly approved by Phil Karn, KA9Q.

The KA9Q NOS TCP/IP package began life way back in 1985 on a surplus Xerox 820 computer board running CP/M with a 4 MHz Zilog Z-80 CPU, 64KB of RAM and a 8" floppy drive holding all of 243KB. Later, it moved to the IBM PC with the 8088 and 80286 CPUs running MS-DOS.

KA9Q NOS was only the second known implementation of the Internet protocols for low-end computers. Unlike PC/IP, KA9Q NOS could simultaneously act as an Internet client, a server and an IP packet router, and handle multiple client and server sessions.

KA9Q NOS attracted many contributors and became widely used throughout the 1980s and 1990s in amateur packet radio and various educational projects. In a way, it was the Linux of its day.

KA9Q NOS became the basis for several low-end commercial dialup terminal servers and routers. It influenced the development of the Internet protocols and implementations, including the Linux kernel.