RSTS certainly should have an FCS library, at least I assume so because it's hard to see how one would build RSX programs to run on RSTS otherwise. I don't know what IND is. Could you give some more background about what ZEMU is and what you're trying to do? Also, what version of RSTS? paul On Jun 18, 2013, at 7:43 PM, Julian Wolfe wrote: Hi all, I'm trying unsuccessfully to build a copy of ZEMU on RSTS/E. Because RSTS/E has no FCS library or IND program, it fails to run either a prebuilt RSX binary or even start a compile on RSTS. Even if I did have IND, there is no SYSTEM.MLB for RSTS to pull symbols from. Can anyone help me out with a prebuilt binary for RT-11 without split I&D, or offer expertise on an RSTS build? Julian