Windows 3.x / Communication
CiscoWorks 3.0 for Windows 3.1 / Windows 95. This includes CastleRock SNMP 4.1c. This is a network management program, from the dark ages. It's good enough to do basic SNMP tasks. All the networking programs are WIN16, so running it directly on a Win64 based machine is out of the question, you need an emulator. Combine this with GNS3 and you can be a Jr Network Engineer in no time!
DOS / OS
IOS Source Code 11.2-8
This is the leaked IOS source code. This version covers m68000 & MIPS R4000 based devices such as: c1000,c1005,c4000,c3620,c3640,c7200,c7100,ls1010,rsp,as5200,ls2020,ls2080,ags,alc. This source will not build cleanly as it lacks a SNMP generation tool. All builds were done on Solaris, using cygnus SPARC-m68k, SPARC-MIPS and SPARC-PowerPC cross compilers (gcc).