Machine type: Shared-memory multi-vectorprocessor.
Models: Cray Y-MP
Operating system: UNICOS (Cray Unix variant).
Compilers: Fortran, C, C++, Pascal, ADA.
The Cray Y-MP is probably still the machine from Cray Research Inc. that is most abundantly around as far as large vector processors are concerned. Its successor the C90 may gradually replace it. The Y-MP is a shared memory MIMD machine with up to 8 processors and a very high memory bandwidth: every processor has two ports to load from memory and one two store to memory, which means that simple dyadic operations can be supported at full vector speed. This property is also present in most other Cray models.
Each CPU contains two arithmetic functional units which can be chained to deliver 2 results/cycle. At a rate of 6 ns this amounts to a theoretical peak performance of 333 Mflop/s per CPU. The actual performance can be a very percentage of the theoretical peak as can be seen from the table above.