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The Convex C4 series. (C4/XA)

Machine type: Shared-memory multi-vectorprocessor.
Models: C46x0,
Operating system: ConvexOS (Convex's Unix variant).
Compilers: Fortran, C, C++, ADA, Lisp.

System parameters:


The C4600 series is the fourth generation of vectorprocessors from Convex. Unlike in the former C3800 series, with a maximum of 8 processors, the highest number of processors is four in the C4640 model. A major difference with the former generations is that more functional unit sets per CPU are present: six general purpose functional units. This brings the number of floating-point results per cycle to 6 in the ideal case. Because the floating-point units are general the opportunities for linking or independent processing are increased with respect to specialised multiply and add pipes which increases the scheduling density of operations. In addition, some logical operations can be done in the functional u nits which enables 32-bit convolutions to be done in excess of 1 Gflop/s (this is called the ``extended architecture'', XA, in Convex jargon).

As in the former C3400 and C3800 GaAs components are used to arrive at the cycle time of 7.41 ns. Also like in these former models, there is difference in speed of a factor of two between single precision (32 bits) and double precision (64 bits) calculations.

As for the Convex Exemplar SPP-1000 (see below) an ''application compiler'' is available that is capable of interprocedural analysis. This can greatly enhance the vectorisability of some codes and in general is beneficial in optimising large codes.
Tue Nov 14 15:39:09 PST 1995