Hi Mark, I can only speak for the VAX side of things, but ymmv and possibly similar? I?ve seen this with VMS on the VAX simulator. I think the idle loop detection changed a while back (perhaps on KLH10 also?) so it wasn?t detecting the vms idle loop correctly and thus emulating every cycle, driving the cpu to 100%. There was an option I used to feed it in the .ini which was: SET CPU IDLE=VMS But this has not made much of a difference for a long while. On-topic, SET CPU IDLE=NETBSD has worked for me. I am unsure of the reasoning. Regards, Al Boyanich *From:* owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] *On Behalf Of *Mark Abene *Sent:* Sunday, 4 March 2018 7:03 PM *To:* hecnet at update.uu.se *Subject:* [HECnet] KLH10 not idling host CPU I'm posting this here in the hopes that there are other KLH10 emulator users on HECnet. I've been using KLH10 with the tap patches for years and years, and idling has always worked fine. At some point over the recent couple of years, idling stopped working for me on linux (I run ubuntu 16.04.4 LTS with latest updates as of yesterday, on a 64-bit intel machine). My CPU is stuck at 100% utilization, without even starting an emulated OS (I run TOPS-20). In fact, as soon as I type "GO" in KLH10 and before doing anything else, the CPU immediately shoots to 100%. Is anyone else seeing this? In older versions of ubuntu/linux this didn't happen. Thanks, Mark Disclaimer The information in this e-mail is confidential and may contain content that is subject to copyright and/or is commercial-in-confidence and is intended only for the use of the above named addressee. If you are not the intended recipient, you are hereby notified that dissemination, copying or use of the information is strictly prohibited. If you have received this e-mail in error, please telephone Fujitsu Australia Limited on 02 9776 4555 or by reply e-mail to the sender and delete the document and all copies thereof. Whereas Fujitsu Australia Limited would not knowingly transmit a virus within an email communication, it is the receiver?s responsibility to scan all communication and any files attached for computer viruses and other defects. Fujitsu Australia Limited does not accept liability for any loss or damage (whether direct, indirect, consequential or economic) however caused, and whether by negligence or otherwise, which may result directly or indirectly from this communication or any files attached. If you do not wish to receive commercial and/or marketing email messages from Fujitsu Australia Limited, please email unsubscribe at au.fujitsu.com.

I can only speak for the VAX side of things, but ymmv and possibly similar? I?ve seen this with VMS on the VAX simulator. I think the idle loop detection changed a while back (perhaps on KLH10 also?) so it wasn?t detecting the vms idle loop correctly and thus emulating every cycle, driving the cpu to 100%. There was an option I used to feed it in the .ini which was: SET CPU IDLE=VMS But this has not made much of a difference for a long while. On-topic, SET CPU IDLE=NETBSD has worked for me. I am unsure of the reasoning.