INFORMATION PROCESSING 89, G.X. Ritter (ed.) Elsevier Science Publishers B.V. (North-Holland) O IFIP, 1989 THE GRAPHICS SUPERCOMPUTER: A NEW CLASS OF COMPUTER Gordon BELL and William S. WORLEY Jr. Ardent Computer Company, Sunnyvale, California, U.S.A. Invited Paper In 1988 a new class of computer, the graphics supercom- tion-set, large memory, microprogrammed, cache mem- puter, was introduced by two start-up companies. As a ory, virtual memory operation, multiprocessors for multi- member of both the supercomputer and workstation fami- programmed use, and, finally, vector processing); to the lies, the graphics supercomputer enables both high-per- VAX "minicomputer"; and to the truly interactive "per- formance computation and high-speed, threedimensional, sonal computers" and "workstations." interactive visualization to be performed on a single, inte- grated system. In Ardent's TITAN system, high floating peak computational power as measured in millions or point operation rates are provided by combining the fastest billions of floating point operations per second for scien- RISC microprocessors with traditional supercomputer tific use. This line has been characterized by the Seymour components such as multiple, pipelined vector processors Cray designs which employ the fastest clocks, hardwired and interleaved memory systems. This has resulted in much logic, and extensive parallelism through pipelining and more cost-effective computation and a clear diseconomy of multiple functional units. These systems evolved to vec- scale over supercomputers and minisupercomputers. For tor processing, multiple processors for multiprogram- users ofworkstations that lack the benefits of supercomputer med use, and finally to the parallel processing of a single components, the graphics supercomputer can be used sim- computation. Lower cost supercomputer lines based on ply as a workstation which provides fiveto-ten times more extensive parallelism were extended in the early 80's with performance for important classes of applications. the "minisupercomputer" by Alliant and Convex, and with the introduction this year of the "graphicssupercom- Ardent has introduced a next generation, extendible, object- puter" by Ardent and Stellar. oriented dynamic rendering environment, Dort, as a de- facto standard for the graphics supercomputer computing The importance of the UNIX operating system to the evolu- paradigm, Borden [I]. The graphics supercomputer en- tion of computing should be emphasized. It has permitted ables new applications in computational chemistry, compu- users of one class of system to have compatibility with ma- tational fluid dynamics, real time simulation, animation, chines of other classes of systems. We believe that both mechanical design and engineering, interactive visualiza- horizontal (machines within a class) and vertical (machines tion, and image processing as typified in medicine, surveil- of different classes) compatibility are essential for accelerat- lance, and petroleum exploration. ing the growth of computer use. Machine Classes How Is The Graphics Supercomputer Used? Supercomputers, mainframes, minicomputers, super-mini- Unless a new class of computer engenders a new type, style, computers, mini-supercomputers,workstations,and personal logistics, or economics of use which differentiates it from computers have f&med and evolved as distinct computer other classes of comuuters. it is unlikelv to be successful. classes, differentiated primarily by price. Each new class that Although the graphics su&computer 'has been on the formed has been based upon key new technologies; a market market for less than one year, radical new uses are emerging of users with corresponding application and style-ofcomput- in science, engineering: medicine, finance, arts, training ing needs; and start-up companies who built and introduced (real time simulators), and intelligence/surveillance based the new type of computer. While the record shows that on coupled high computation and interactive visualization established companies do not innovate fundamentally new capabilities. products, they frequently are a source of key people and serve as initial market outlets for those companies that do inno- At the same time, many of the uses of a graphics supercom- vate. Ultimately, if the market is a large one, they adopt the puter are simply evolutions of the uses of structures that have new class idea from a start-up. Examples include IBM's been in operation on ordinary workstations. In effect, a adoptions of the minicomputer from DEC and the PC from graphics supercomputer can be viewed as a very high per- Apple, and DEC's recent adoption of engineering worksta- formance workstation-the quantitative differences in its tions from Apollo and Sun. performance capabilities result in qualitative differences in the applications and manner in which it is used. In this Figure 1 shows how various members of established com- regard, compatibility at many levels is essential for training puter classes have occurred in time, following two "main and the preservation of software investments. This includes lines" of development: common hardware busses, adapters, and protocols; Local Area networks; data formats; programming languages and general purpose processing for both commercial and compilers; operating systems, including the system, window- scientific use, as characterized by the thread of develop ing, and user interfaces; graphics languages; and end-user ment from the Univac I "mainframe" in 1950, to the IBM applications. S/360, S/370 ... 3090 evolution (general complex instruc- C.G. Bell and W.S. Worley EVOLUTION OF COMPUTING STYLES Supercomputing for Science and Engineering ....................................................... Ordinary General Purpose Office, Transaction, and Data Processing Computing 1980 Figure 1 In other cases, the graphics supercomputer simply can sub- tion of graphics supercomputers. Very large scale integrated stitute for an ordinary computer of less power, such as a CMOS circuits can be used to build both large and fast super-minicomputer (e.g. VAX 8600), a mini-supercom- memories; fast, simple, pipelined scalar processors (i.e. RISC puter with equivalent power and higher price (e.g. Alliant or microprocessors); pipelined floating-point arithmetic units; Convex), or a mainframe (where the performance is often an and large, complex application-specific ICs. Large gate ar- order of magnitude worse than a supercomputer). In some rays provide the control for the complex vector units and instances, the graphics supercomputer is used together with graphics processors which compose the heart of the graphics a supercomputer, as a workstation for visualization and for supercomputer. The main architecturalingredients of graph- ancillary high speed computations. ics supercomputers are RISC microprocessors, vector proc- essors, and specialized graphics processors. Components The most interesting and perhaps most important aspect of realizing each of these architectural elements became pos- the graphics supercomputer is that it is the avant garde for sible due to large scale integrated circuits. personal supercomputing. We believe that the productivity of scientific researchers can significantly be augmented by Few now debate the pro's and con's of RISC architectures, the availability to every scientist and engineer of his own, the RISC revolution is over. RISC won. Today, RISC micro- personal supercomputer. A graphics supercomputer of the processors set the performance/price standards for worksta- power of the Ardent Titan System, which is usually sufficient tions, technical computation, and even some commercial LOsubstitute for a share of a central supercomputer, at a cost systems. They simply cannot be equaled by CISC microprc- below $50,000, could make this possible. The next genera- cessors, mainframes, or minicomputers. tion graphics supercomputers are expected to reach this performance/price, enabling the transition to full distrib- The Dower of vector Drocessors derives from the vector uted supercomputingwhere every scientist and engineer has paradigm that is very generally applicable and equivalent to one on a desk, instead of timesharing a large, single system. concurrent issue and execution of many scalar instructions. The Ardent Titan vector processor, for example, simultane- New Technologies Have Enabled the Graphics ously executes two loadvector register pipelines (pipes),one Supercomputer Clans to Form store pipe, and a one-tc-three input operation pipe. Each completed pipe operation includes executing its main op- Each of the computer classes cited earlier was formed ini- eration, advancing register and memory addresses, decre- tially, and evolved subsequently, based on new circuit, and menting a vector length, testing for completion, and con- software technologies. The large scale integrated circuit is tinuingoperation until complete. In sequential form, if each the basic hardware technology that has enabled the construc- of these elements were done by a single instruction, and The Graphics Supercomputer assuming self-addressincrementingload/store instructions, Applications Needs are Critical for Market Formation each Titan vector unit cycle would require approximately sixteen scalar instructions. In effect, specializedvector hard- While technology lies at the root of a new computer class, ware permits sustained, pipelined execution of sequences of corresponding applications' needs must exist and be in highly generic operations.