other: 0.233 semantic: 0.223 device: 0.086 graphic: 0.085 files: 0.052 debug: 0.050 permissions: 0.048 network: 0.042 performance: 0.040 PID: 0.035 vnc: 0.034 socket: 0.028 boot: 0.027 KVM: 0.017 debug: 0.206 PID: 0.145 other: 0.117 device: 0.098 files: 0.087 network: 0.070 performance: 0.062 boot: 0.054 semantic: 0.041 socket: 0.039 vnc: 0.033 graphic: 0.019 KVM: 0.016 permissions: 0.013 It dumps when following this tutorial on hello world os http://mikeos.berlios.de/write-your-own-os.html Following the steps, it works on ubuntu, but on osx, it ALWAYS dumps. The referenced website is no longer available, thus setting this ticket to INVALID. Please feel free to re-open it if the information is available somewhere else and you can reproduce it with the latest version of QEMU.