For the last several years, the center has annually doubled its archive of files. In addition the average file size is increasing. With larger and faster systems, research scientists are producing much more data and doing it more frequently. The storage habits of NCSA users are fairly stable according to analysis performed by HPDM staff. As files grow older, the rate of access plummets.
Staff know that many stored files are never retrieved.
HPDM staff say that these numbers have not changed a great deal in the last decade. The main considerations in designing the next storage system are cost and speed. Tape prices are quite inexpensive. But the real price tag for a tape system must include the expenses for all the system components. The cost of a tape system moves closer to the price of disks when these components are included.