MIX is Donald Knuth's mythical computer as described in his monumental work
The Art of Computer Programming. As any of its real counterparts, the MIX
features registers, memory cells, an overflow toggle, comparison flags,
input-output devices, and a set of binary instructions executable by its virtual
CPU. You can program the MIX using an assembly language called MIXAL, the MIX
Assembly Language.

MDK (MIX Development Kit) offers an emulation of MIX and MIXAL. The current
version MDK includes the following applications:

   - mixasm: A MIXAL compiler, which translates your source files into binary
     ones, executable by the MIX virtual machine.
   - mixvm: A MIX virtual machine which is able to run and debug compiled MIXAL
     programs, using a command line interface with readline's line editting
     capabilities.
   - gmixvm: A MIX virtual machine with a GTK+ GUI which allows you running and
     debugging your MIXAL programs through a nice graphical interface.
   - mixguile: A Guile interpreter with an embedded MIX virtual machine,
     manipulable through a library of Scheme functions.
   - mixvm.el: An elisp program which allows you to run mixvm within an Emacs
     GUD window, simultaneously viewing your MIXAL source file in another
     buffer.