DREAM: a special-purpose architecture for large scale finite difference calculations

Abstract

Presents the concept of DREAM (Disk REsource Array Machine), an architecture designed for large-scale finite difference simulations. On preset computers, the size of finite difference calculation is limited by the size of the memory. The DREAM system uses magnetic disks as the main memory. With main memory made of magnetic disks, one can construct a machine with 100 times larger memory for the same cost. With the DREAM architecture, neither the data transfer rate nor the access time of the disk unit limit the computing speed. The data transfer rate is increased by accessing a number of disks in parallel. The access time becomes negligible for finite difference calculations in which all data are accessed in long vectors. A DREAM system with 2 GByte memory and 40-80 MFLOPS speed costs around 20000 dollars. A system with a 1 TByte disk would cost several million dollars.<>