Bob, I've have had no luck with idle on either simh or klh10 (for TOPS20). I'd planned to post to alt.sys.pdp10 but hadn't gotten around to it yet. If you run across anything, I'd be interested. I may experiment a bit this weekend if I get the time. Joe On Thu, Aug 4, 2011 at 5:29 PM, Bob Armstrong <bob at jfcl.com> wrote: Are there any HECnet'ers running TOPS20 on simh? Have you gotten the idle detection to work? I set up a TOPS20 system with simh (simh v3.8.1 on Ubuntu, TOPS20 v4.1 clean install). The installation went fine with no problems, but I cannot get the idle detection feature in simh to work. I say - pdp10 sim> att rp0 tops20-4.1.rp06 sim> set cpu tops20 sim> set cpu idle tops20 sim> show cpu CPU, idle enabled, stability wait = 20s, 1048KW, TOPS-20 sim> b rp .... Everything boots and runs fine, but simh uses about 98% of the host CPU and never goes down. In an hour of wall clock time the pdp10 process uses about 58+ minutes of CPU time. Clearly the idle detection isn't working for me. I did try posting this question on the simh list, but got no comments so I guess nobody there is using TOPS20. And yes, I could use KLH10, but AFAIK KLH10 has no idle detection feature at all. Thanks, Bob