The causes of abnormal terminations are divided into two categories: internal and external. The difference between these two types of causes can determine whether a process generates a program dump, and whether the process restarts automatically. To be more specific, the FAULT option of the OPTION task attribute causes a program dump if a process is discontinued by an internal cause. The DSED option of the OPTION task attribute causes a program dump if a process is discontinued by an external cause. The RESTART task attribute causes a process to restart only if it is terminated by an internal cause. If the task has not executed any user code, the RESTART count is ignored. For example, RESTART is ignored if a task fails to run because the codefile is too old to run on the current release.

An abnormal termination is considered to be due to an external cause if the HISTORYCAUSE and HISTORYREASON task attributes have any of the following combinations of values:

An abnormal termination is considered to be due to an internal cause if the HISTORYCAUSE and HISTORYREASON values are not any of the combinations listed in the preceding table.