KA9Q NOS is an amazingly powerful piece of software considering it contains the above listed servers and enough routing functions to act as a SLIP or PPP server. So, if you're interested in using an old PC to create a SLIP server, you can use NOS for the job and get a nearly full fledged Internet server at the same time.
The versions of KA9Q NOS that used to run on this server were based on JNOS110g and, before that, on Nos11c. It was my hope that the JNOS code would be more stable as well as add new features to the server. The JNOS variants that I used to run were compiled for 80386 systems and thus require a 386sx or better. It is possible to recompile Nos for 8086 systems, though these don't run as well since they lack the memory management possible on 386 systems. The minimum I'd recomend for a NOS server is a 386sx with 2MB RAM. When Nos is run on 8086/8088 systems, memory will be tight as these systems lack the memory management (UMB, HMA) possible on a 386. Nos needs all the RAM it can get and is generally more stable when more RAM is available. Using EMM386 on a 386, it's possible to give Nos over 700kb of RAM to play with.
I had lots of trouble with my compiles of modified versions of JNOS and recomend that if you want to try out a modified JNOS with gopher and http servers, you try Karl-Heinz Weiss's yanos. It's quite stable and has many features not found in Nos11c based nos's. Around 11-94, I installed Linux on Inorganic5, and shortly after that, I removed KA9Q completely, to make more room for Linux.
Linux is capable of acting as a SLIP/PPP/dialup server as well and can generally do just about anything Nos can do (and more) better. Linux, however, is Unix-like, which means it's nothing at all like running a Dos system. Administering a Linux system might be much more than you want to deal with if you just want to setup a system at the office to let you SLIP in to the office net or internet. Linux also has much more demanding hardware requirements. It will not run on anything less than a 386sx with 2MB RAM, and runs much better with faster processors and much more RAM. Nos, on the other hand, can be setup as a dedicated SLIP server on an 8086 with 640kb and a single floppy drive. For more information on Linux, see the Linux Documentation Project.
In order to setup a NOS based dialup SLIP server, you will need the following:
Executables, source, documentation, and a helpful how-to file (slip.txt) are all available via anonymous FTP and gopher at inorganic5.fdt.net under the /pub/nos directory.
Searchable documentation for KA9Q NOS11C