THOR also keeps track on the disk space on the local VSAT disks. A file is generated with a disk-space reading every 6 hours on the 4 disks. If a disk is 95% full THOR will send a mail to the shifter, informing that it is time to back up this disk. Once again after a tape has been inserted and an acknowledgement have been sent to THOR, a backup is done automatically.
To cure the problem with a full disk, files have to be removed. It can not be the shifters responsibility to know which files are important and should be saved and which files are not. Everybody involved with the VSAT disks must contribute to generate this information. To make this task as easy as possible THOR generates a directory tree with information of the number of files and the total size in each subdirectory.
To select which files that should be saved, THOR also generates a list of all the files on the disk. The shifter should then tell all involved persons to mark the files they want to save in this list. When this has been confirmed, the backup tape from the disk should be inserted in the tape station and acknowledgement sent to THOR. Then a program called Bacman will be started by THOR, which will delete all files that not have been marked.
This feature have become less important over the last two years, as many people have left the VSAT project. It was integrated in THOR from the beginning when the disk-space situation was very critical and a lot of people were using the system. In these days the shifter have control of over 90% of the available disk space in comparison to about 40-50% before. The framework is however still resident in the code in case the VSAT project should get a boost in popularity. This can be expected at the end of data taking in year 2000, when the whole disk-space released from data processing will be available for data analysis.