The trouble seems to be with libata. http://bugs.donarmstrong.com/cgi-bin/bugreport.cgi?bug=402751
The absence of logs for the complete freeze points in direction of trouble with the harddisk (and the system unable to cough up what is happening to a log file). -- system locking up (forcing a hard reboot) https://launchpad.net/bugs/89362 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
