Super class for backup tasks.
Back up tape device if it is save to tape
This callback method is invoked by the
%ValidateObjectmethod to provide notification that the current object is being validated.
If this method returns an error then
This method is responsible for executing the task.
At the scheduled time, the Task Manager creates an instance of this object, sets any property values using the stored "settings" for the task, and then invokes this method to execute the task.
In order to execute a real task, override this method in a subclass.