An analysis of the Cray-1 computer

The Cray-1 is an extremely high-speed computer, intended to be used for large floating-point scientific computations. However, it is a well-balanced machine that can gracefully be used on a wide class of problems. The machine has two major architectural innovations: (1) 128 backup registers which represent a new layer in the memory hierarchy, essentially a programmer or compiler-managed cache, and (2) 8 vector registers holding up to 64 words each, and operated on by vector instructions. In this paper, we will describe the entire machine, discuss efficient ways to use the 656+ programmer-accessible registers, and discuss some of the design shortcomings.