Madcrow> Thanks for that huge list... That was exactly what I was Madcrow> looking for... As for the "what bus" question, it doesn't Madcrow> really matter to me as I can emulate either depending on Madcrow> what hardware I need to emulate and what software I want to Madcrow> play around with (simh is nice that way) MSCP disks are a nice way to do disk emulation, because the OS shouldn't really care what size you pick (up to whatever max drive size it can handle). At least that's true with E11; I don't know about SIMH. In MSCP, the OS asks the drive for its capacity. So it isn't necessary to emulate a specific "real" disk. I usually just pick a size that's "big enough", let E11 call it an RA81, and RSTS just believes the size it sees. Conversely, for non-MSCP drives, you have to match the size since the OS driver has the drive capacity wired into it. paul