A while back, there was a brief discussion on the list about microprocessor simulators running on larger systems. Some interest was expressed in the simulators I was involved with some years ago. I've put together some details and some code here: Z80 simulator in FORTRAN IV for the MUSIC/SP IBM mainframe operating system http://software.beyondthepale.ie/music/z80/ 6502 / BBC Microcomputer simulator in FORTRAN and 370 assembly for MUSIC/SP http://software.beyondthepale.ie/music/y6502/ 6502 / BBC Microcomputer simulator in FORTRAN and VAX assembly for VAX/VMS http://software.beyondthepale.ie/vms/y6502/ All the bits and pieces are provided to run the first two simulators on the freely available "MUSIC/SP Demo system" running on Sim390 or Hercules and the latter one on any reasonable VAX/VMS platform or simulator. The original unmodified code is also there. With the addition of a BBC Micro BASIC ROM, it is possible to run text based BASIC programs such as http://software.beyondthepale.ie/bbcmicro/survival/ (an adventure game) on the latter two simulators. Regards, Peter Coghlan.