Mainframes

IBM may be the largest supplier of supercomputing power. It has installed significant computational power in its 3090 mainframes with vector-processing facilities. Dataquest has estimated that 250 of the 750 3090-processors shipped last year had vector-processing capability. Although a 3090/600 has 25 per cent of the CRAY Y-MP's LINPACK peak power, its ability to carry out a workload, as measured by Livermore Loops, is roughly one-third that of a CRAY Y-MP/8.

But we see only modest economic advantages and little or no practical benefit to be derived from substituting one centralized, time-shared resource for another. For numeric computing, mainframes are not the best performers in their price class. Although they supply plenty of computational power, they rarely hit the performance peaks that supercomputer-class applications demand. The mainframes from IBM—and

even the new DEC 9000 series—suffer from the awkwardness of traditional  architecture  evolution. Their emitter-coupled-logic (ECL) circuit technology is costly. And the pace of improvement in ECL density lags far behind the rate of progress demonstrated by the complementary-metaloxide-semiconductor (CMOS) circuitry employed in more cost-effective and easier-to-use supersubstitutes.