Sequent Computer Systems Inc has unveiled its second generation multiprocessing computer architecture, NUMA-Q, and said to expect products using it in the second half of next year (CI No 2,704). It will be based on Non-Uniform Memory Access and will use Intel Corp’s Pentium Pro, and the company said the system will offer 10 times the performance of current symmetric multiprocessing systems but at prices in keeping with the personal computer components it will use. In addition to the better price-performance, the company said the system’s other attraction is that it offers binary compatibility with existing Symmetry servers so Windows NT and Unix will run unchanged on it. It believes this will give it the edge over massively parallel architectures for which programmers have found it difficult to develop applications that truly take advantage of the parallelism. The first machine is likely to be a 256-processor affair. Data General Corp, which is also working on Non Uniform Memory Access, is on schedule to beat Sequent to market, but is planning a 32-way machine. Sequent’s architecture is the culmination of two years’ work in which it built a system to use Intel’s quad boards. In the machine, each processor has its own cache memory and the caches talk to each other via IQ-Link to create the illusion of shared system main memory. IQ-Link is the intelligent interconnect the company has designed which it described as a grown up cache controller and which avoids the bottlenecks associated with symmetric multiprocessing. Sequent said the system will scale to hundreds of processors, with no visible bottleneck and provides an easy to programme environment. The system is neither shared everything, as in symmetric multiprocessing, nor shared nothing, as in parallel, but a ‘shared-when-you-want’; it can configure itself dynamically under software control said the company. The quad boards, symmetric multiprocessing blocks that are configured into what is essentially a parallel structure, are expected in about nine months. Sequent said that with their launch, symmetric multiprocesing on the desktop will become a commodity overnight. The boards have been designed by Intel with technological input from Sequent, which has tinkered with them, putting the on-board memory and input-output closer to each processor so there is no need to go out and use bandwidth on the interconnect between the quad-processor modules. Around this configuration of boards runs a Fibre Channel input-output system that links into every board giving each processor direct access to every peripheral attached to the system. It is not a backplane, said Sequent, but a daisychain connection between quads.
