To inform the shifter about the progress and status of THOR a number of different types of output information is generated. If THOR should crash for some unknown reason, it is very essential to be able to look in the log file. But as THOR is a DCL command file and should be run all the time during the year, such a log file would take up a tremendous amount of disk space and would be impossible to load from an editor. To solve this problem THOR works as second level process. When the log file has reached a critical size the second level program ignites an other process and then self terminate.
This new process then sends a mail to the shifter informing him about the stop. After this it waits for one hour before it deletes the old log file and start the THOR program again and self terminate. If the shifter want to stop the execution of THOR, it is best to do it during this hour. The rest of this chapter will describe other forms of output that is generated to guide the shifter.