ftp://ftp.gnu.org/gnu/mdk/ and mirrors of that site (see list of
mirror sites at http://www.gnu.org/order/ftp.html) . GNU MDK provides a simulator of D. Knuth's MIX computer, and a
development environment to write, run and debug MIXAL programs on it.
New in this release: ** In gmixvm, when the mouse pointer is over a MIXAL source line, the status bar shows the value of the variables appearing in this line. ** The current symbol table can be displayed, in gmixvm, using the menu command Debug->Symbols... ** Bug fix: the load, compile and run file dialogs now get the correct filename under linux. ** Bug fix: fonts used by gmixvm are now always correctly saved. ** Bug fix: 'psym' now works correctly in gmixvm. ** Bug fix: the symbol table for a MIX file is now correctly recovered both in gmixvm and mixvm (negative values where incorrectly converted to a positive value). Visit the MDK home page at http://www.gnu.org/software/mdk/mdk.html. Bug reports should go to email@example.com. Enjoy!  GNU MDK source and binary packages can also be downloaded from http://sourceforge.net/project/showfiles.php?group_id=13897&release_id=35894