d the quantity of information for 
each type of storage media. Then with estimates of the reliable lifetime of the storage media 
and information of system loading, etc., the repository can estimate the time required for 
storage media migration, or refreshing or copying between media without reformatting the 
bit stream. The repository can then set triggers for initiating the action at an appropriate time 
so the actions will be completed before data is lost. Copying large quantities of data can take 
a lo