I was looking at some of the diagnostics on the KLAD pack http://pdp-10.trailing-edge.com/klad_sources/index.html and I notice that this one (DAKAA - basic instruction test) has a bunch of interesting output at the end of the .SEQ file http://pdp-10.trailing-edge.com/klad_sources/01/klad.sources/dakaa.seq.html The first part is just the diagnostic operating instructions and the second part is the MACRO-10 listing, but at the end there's the output from what appears to be a KA10 simulation. The header on each listing page says "KASIM VER 0.2 19-JAN-77" - did DEC actually write a KA10 simulator ? And it's apparently more than just a simple instruction simulator too, because for each instruction there's a complete trace with all the internal time states and internal register contents for the KA10. It must be an attempt to model the internal architecture of the KA CPU. Does anyone know any more about this program? Does anyone have a pointer to the source for it? Tantalizingly there's a KASIM.SAV on the KLAD pack, but that's all. Bob