Each processor has 256 MBs of memory, providing a total of approximately 65.6 GBytes for user applications. Users employ a number of processors so that there is enough memory for the task they wish to perform. The use of multiple processors requires a parallelized application. Typically parallel applications hold only the data that each processor will be working with in local memory and a small set of replicated data. Each processor works on the local data exchanging data with other processors so as to correctly perform the desired computation.
Scalable algorithms can run on a range of different numbers of processors.
Often in scientific and engineering codes this occurs naturally so long as the problem size increases with the number of processors, a particular problem size will have a range of processor number for which it is efficient. If the number of processors is limited by features of the algorithm, then users should either modify the algorithm, or the amount of memory on each processor can be increased to suit the problem size. The ARSC T3E system has 522 GByte of disk storage divided between users and system, and nearline storage of over 300 TB through a tape silo. With DMF, files are moved from disk to tape automatically to prevent filesystems from becoming full. The file still appears in the users directory, and is restored automatically when the user next accesses the file.