On 7 March 2000, the Scientific Computing Division began working with StorageTek engineers to add two new Automated Cartridge System silos to the Mass Storage System at the National Center for Atmospheric Research. This brings the number of MSS silos at NCAR to five.

The new silos have a combined data storage capacity of 240 terabytes, which doubles the amount of data that can be stored in the MSS. The silos also provide faster access to data and allow SCD to migrate existing data to newer and more reliable storage media.

Often called the "crown jewel of NCAR," the Mass Storage System is the most capacious of any scientific research center in the world. With the new silos, storage capacity has increased to more than half a petabyte.

Ten StorageTek 9840 tape drives are attached to the new silos. Each silo holds 6,000 STK 9840 tape cartridges; each cartridge holds 20 gigabytes of data. (By 2001, new 60-gigabyte cartridges will be available.)

When a user requests data from the MSS, a robot inside a silo mounts a cartridge and the data are accessed by one of NCAR's high-performance computers. A robot can mount 350 cassettes per hour. (On average, an MSS file retrieval from a silo takes one or two minutes. This includes mounting the cartridge, positioning the reader to where the data resides on tape, and transferring the data.)

For more information about the MSS and how to access it, see the technical UserDoc, "Introduction to NCAR's Mass Storage System."