I finally got a copy of the MRRT manual to read (thanks, Steve!) and it does require that you have RT11 v4 to build MRRT. I'm sure a lot of the sources were shared, but it looks like there were at least some components (e.g. MRTGEN, DLLOAD) that were unique to MRRT11. There must have been an extra diskette or tape that you had to get from DEC that had the MRRT components. So I'm still stuck looking for a copy - if anybody has it or has seen it, I'd love a pointer. Thanks, Bob Armstrong