continued from page 1A tinuously enhanced since then.

"It's valuable for computing networks because it can be used for a wide variety of file storage and access requirements," said Bill Collins, Los Alamos project leader for the CFS.

The system is unique in its ability to store large quantities of archival data-files that are saved for a long period of time and seldom used while at the same time providing fast retrieval of active files.

The CFS is organized as a hierarchy of storage systems where files are automatically moved between the storage systems based on their size and idle time," Collins said.

The system can be used by nearly any type of computing equipment from giant supercomputers to small personal computers.

"The use of CFS for inactive file storage is especially important for supercomputers where the disk is

very expensive and the space limited," said Collins.

"For example, files that need to be permanently saved are stored in the Common File System and then deleted from the supercomputer disk when they become idle," he said.

"Because of this flexibility, the CFS provides users with essentially unlimited file storage," Collins said.

There are no space limitations imposed by the CFS because there is no pre-allocation of space," he said. "Files in large demand are immediately available on disk, while those not in immediate use are automatically transferred to less expensive storage."

Also, by storing their files on the CFS, users can compute on any machine in the network and still have easy access to all their files. Files can be shared by different users, yet also can be compartmentalized so that non-cleared users

don't have access to classified files, for example.

Since CFS first became operational at Los Alamos 10 years ago, 19 other systems have been installed at computing facilities throughout the United States and Europe.

Among those are Sandia National Laboratories and the Air Force Weapons Laboratory in Albuquerque, European Centre for Medium-Range Weather Forecasts in England, West Germany's Atomic Energy Research Facility, Oak Ridge (Tenn.) National Laboratory and the San Diego Supercomputer Center.

This is the first software license negotiated under the recent, comprehensive Department of Energy copyright policy," said Sam Freund of the Lab's Intellectual Property Office. "Royalty income will come directly to the Laboratory instead of the University of California."

-William Heimbach