As many of you all know, I'm trying to get an HP2000 TSB system up and running. Purist that I am, I am using only original HP gear for it. However, I'm also thinking ahead to the power consumption (ie the Amps) that the system draws. I might not be able to afford to keep it online all the time. So I have been starting the mental exercise of laying out how to best design an emulator. The overal design layout is complete, but there is a low-level issue I can't get my brain around and thought someone here might have some input on the following: The 2100A/S or 21MX/E systems were microcoded. Matter of fact, the control processor on those systems is 24 bit, while the appearance at the non-microcode level is a 16 bit machine. Should I write my emulator to process the microcode instructions or the 2100A/S or 21MX/E instruction set that the microcode implements? I was planning on the latter, however one argument for the former is that HP did release special ROMS to extend the instruction set for special applications (DMS for one, SIS, FFP, 2000Access IOP for others). I would like users to be able to set the emulator to a given hardware configuration (ie. command line options to turn on the DMS, SIS instruction sets) rather than assuming a machine configured with all available options. Each I/O interface card would have it's own loadable module, so they can select what cards are installed in what slots, etc. I just have the gut feeling that there's some obvious reason to do one or the other that I'm missing... Yes, I am aware of Jeff Moffat's 2100 emulator; nothing at all against his code, but I'd just prefer to start from scratch (this means I'm idiotic or masochistic or more than likely both) <Grin>. I'll write it in C on Unix (FreeBSD) but make sure the makefiles are setup so DOS porting is just a configure argument. Heck, the whole project is worth it just to see TSB running on a Pentium II 400! Any input appreciated! Jay West