Each Arbortext PE サブプロセス has a flag which is set any time it returns a fatal error. When a work thread detects an unusable Arbortext PE サブプロセス, it sets a flag that records the state of the Arbortext PE サブプロセス. At a later time, the work thread scans all running Arbortext PE サブプロセス and requests the operating system to terminate any with the hung or fatal flag set to true.