I use some proprietary software (but never as native code; some of the problems are most relevant when it is run as native code), although I intend to replace them with free software when possible (for example, I am currently in the process of writing Free Hero Mesh, as a replacement for Hero Mesh (which is very slow on DOSBOX), that is compatible with Linux, and preferably also BSD; later I may also make FreeZZT as a replacement for ZZT).