http://www.bttr-software.de/ports/

This page holds DOS versions of various open-source software. These
software titles have been developed by different authors not
associated with BTTR Software, but members of BTTR Software made those
DOS versions.

A build is just a recompile of the original source code using a
compiler capable of producing real DOS binaries. A port is similar to
a build, but additionally required changes to make the program work
for the DOS platform. "*b.zip" files contain binaries and
documentation for end-users. "*s.zip" contain fully configured source
code for developers.