NAS-CURRENTSTATUSANDFUTUREPLANS N 87- 26 000 F. R.Bailey NASAAmesResearchCenter MoffettField,California INTRODUCTION derived from assuming a solution in 15 min of central-processor time are compared with the capa- The Numerical Aerodynamic Simulation (NAS) bilities of several supercomputer generations Program had its inception in 1975 at the Ames (Peterson et al., 1985). As indicated, current Research Center (ARC) when a small group of supercomputers can adequately address inviscid researchers associated with the computational flows, but the computers needed to adequately fluid dynamics program set out to obtain signifi- address more complex Reynolds-averaged approxima- cantly greater computer power and the memory tions to turbulent flows about full aircraft con- capacity needed to solve three-dimensional fluid figurations will not be available until the end of flow models (Peterson et al., 1984). The state of this decade. Large-eddy simulations for complete the art in computational aerodynamics was at the aircraft must wait for future, more powerful point where problems involving complex geometries computers. could be treated only with very simple physical Sparked by this need for increased computer models and only those involving simple two- power, the ARC team spent several years performing dimensional geometry could be treated with more requirements refinement, technical studies, and complex physical models. It was clear that to advocacy that resulted in the establishment of the treat problems with both complex three-dimensional NAS Program in 1983. The ongoing objectives of geometries and complex physics required more com- the program are: (I) to provide a national compu- puter power and memory capacity than was avail- able. This is illustrated in figure I, where the tational capability, available to NASA, Department of Defense, and other Government agencies, indus- estimated computer speed and memory requirements try, and universities, as a necessary element in 1011 -- _.\0_'_ 1010 HSP-2(PROJECTED) 109 CRAY-2 lO8 R EYNOLDS-AVERAGED NAVlER-STOKES O / ILLIAC-IV / CYBER-205, CRAY-XMP / _ 10 7 CRAY-1S /_ AC AIRCRAFT CYBER-203 / W WING CRAY-1 A AIRFOIL 106 CDC-7600 / 105 104 .001 .01 .1 1 10 102 103 104 105 106 COMPUTER SPEED, mflops Fig. I Computer speed and memory requirements for aerodynamic calculations compared with the capability of various supercomputers. 13 ensuring continuing leadership in computational dynamics and computational physics community. The fluid dynamics and related disciplines; (2) to act NPSN will be implemented in phases, with the com- as a pathfinder in advanced, large-scale computer pletion of each phase resulting in an NPSN config- system capability through systematic incorporation uration keyed to the introduction of a new- of state-of-the-art improvements in computer hard- generation, high-speed processor. The NAS Program ware and software technologies; and (3) to provide defined the first two configurations in 1983. a strong research tool for NASA's Office of Aero- These are the Initial Operating Configuration nautics and Space Technology. (IOC) and Extended Operating Configuration (EOC) defined below. An early task in implementing the NAS Program was to ensure its role as a pathfinder in Initial Operating Configuration: providing advanced supercomputing capabilities to the computational fluid dynamics community. To High-speed processor-1 (HSP-I) accomplish this a long-term strategy of instal- 250 million floating-point ling, at the earliest opportunity, a system repre- operations/sec (MFLOPS) senting each new generation of increasingly more computing rate for optimized, powerful high-speed processors was initiated. large-scale, computational aerody- Each generation may be a prototype or early namic applications production model. The strategy, illustrated in 256 million 64-bit words of central figure 2, has already started with the installa- memory tion of Ser. No. 2 of the Cray-2 as the first gen- Integrated and expandable NPSN configuration eration, high-speed processor. Introduction of Common-user interface for all subsystems the Cray-2 required an 8-mo period of test and Medium-band (56 kilobits/sec) communica- integration before production operations began. tions for remote sites The second high-speed processor will be added in Wide-band (1.544 megabits/sec) communi- 1987 followed by several months of test and in- cations to NASA centers tegration leading to an operational capability in 1988. The third generation will replace the first Extended Operating Configuration: in the 1989/90 time frame. In subsequent years, new advanced high-speed processors will replace Additional High-Speed Processor-2 (HSP-2) the older installed systems, thereby maintaining a 1000 MFLOPS computing rate for opti- steady state in which there are two high-speed mized, large-scale, computa- processors, one of which is the most advanced tional aerodynamic applications available. Upgraded subsystems to accommodate HSP-2 and graphics subsystems Coupled with the high-speed processor instal- 6.2 Megabits/sec communications to NASA lation strategy, is the ongoing design and devel- centers opment of the NAS Processing System Network (NPSN). The NPSN is a network of high-speed processors and support computers configured to provide a state-of-the-art, scientific, super- computing environment to the computational fluid 3RD GENERATION HIGH-SPEED PROCESSOR TEST ] OPERATE INTEGRATE 2ND GENERATION HIGH-SPEED ,.I t PROCESSOR TEST [ OPERATE < I/////t,,- !> Q. INTEGRATE < t_ r_ 1ST GENERATION HIGH-SPEED PROCESSOR z < (///// TEST J OPERATE uJ INTEGRATE I ¢J z MID 1986 1988 1989/90 TIME II IB p.- Fig. 2 NAS Program strategy for introducing state-of-the-art high-speed processors. 14 TheNASFacility, completedin January1987, NASIOCDESCRIPTION providesthephysicallocationfor theNASPro- gram.It housestheNPSN,systemsupportand developmentstaff, andcomputationalfluid dynam- TheIOCof theNPSNconsistsof thefollowing ics researchstaff. Thisnew90,O00-ft2 building functionalsubsystems:high-speedprocessor, wasdesignedwithapproximately15,000ft 2 of supportprocessing,workstation,mass-storage,and raisedcomputerfloor whichis sufficient to long-haulcommunications.Theconfiguration, accommodatefutureexpandedNPSNconfigurations. shownin figure 3, is a local-area-network- Approximately15,000ft2 of additionalraised orientedarchitectureconsistingof hardwarefrom floor is availablefor technicalsupportspace, a numberof vendors.Toreducehardwareand laboratories,andusercolocatedworkstation vendor-specificdependencies,theNPSNsoftware equipment.Officespacewasdesignedto allowthe presentsa commonuserinterfaceacrossthesystem computersystemsstaff andcomputationalfluid that providesuserswith the sameenvironmenton dynamicsresearchersto sharethebuilding. These all user-accessiblemachines,i.e., provides accommodationsprovidea strongbondingbetween commonutilities andcommandsonuser-visible thecomputerserviceprovidersandtheir subsystems.Thisuniformenvironmentenables researcherclients. usersto moveeasilybetweenprocessors,allows for easyfile accessandcommandinitiation across TheNASSystemsDivision,formerlytheNAS machineboundaries,andenhancesuser-codepor- ProjectsOffice,at ARChascompletedtheinitial tability withintheNPSN. tasksandis responsiblefor accomplishingtheNAS Programlong-termobjectivesona continuing Theoperatingsystemonall user-visible basis. TheDivisionincludesa skilled staff of computersis basedonAT&T'sUNIXTM System V.2 computerscientistsandengineerswhoare operating system with network software modeled responsiblefor planning,designing,andimple- after the Berkeley 4.2/4.3 bsd UNIX operating mentingtheadvancedtechnologynecessaryto keep system. Jobs on all user-visible systems can be NASattunedto its pathfindingrole. TheDivision run in batch or interactive modes. Communications alsoprovidesday-to-daycomputeroperations; protocols come from the DoD Internet family of ongoingcomputersystemsupportfunctionssuchas protocols, commonly referred to as TCP/IP. hardwareandsoftwaremaintenance;andlogistics; aswellascomputerservicespersonnelto provide thetraining, consultingandtrouble-shooting necessaryto offer premiersupercomput[ngservice to a nationaluserbase. '_71 - COMPUTER TAPES NETWORK SUBSYS. STORAGEDISK (300 GB) CARTRIDGE TAPE __! MICOM i__z__ TERMINALSLHCS _-_---_---_ M!Lnet L IMP ) I VlTALINKI__7 HSP-1 / I ETHERNET . l BRIIDGE I *--1_ NASnet CRAY-2 1 II . _I -_ SPS '_r'_ /i_/ I Irx /I I_ AI III I . -- I AM?.,l AMSPASHLI c_ I V_AX 11/780 .J-J'J VkAAX GWAYSI_]_- I I I ITO C ENA'_'CAL HSDN HYPERCHANNEL COMPUTING FACILITY -_ _ WKS _ _ ,,_ ! I ET"ERN T| Fig. 3 IOC of the NPSN. 15 High-SpeedProcessor Mass Storage Subsystem Thefirst HSP,a Cray-2,is a four-processor systemwith268,435,456wordsof dynamicmemory-- The Mass Storage Subsystem (MSS) consists of or asmorecommonlyreferenced,with256megawordsan Amdahl 5860 mainframe computer, Amdahl 6380 (whereeachik equals102464bits/word)of disks, and IBM 3480 cartridge tape drives; this dynamicmemory.Thefourprocessorscanoperate subsystem serves the global online and archival independentlyonseparatejobsor in a multipro- storage needs of the NPSN. The MSS checks and cessingmodeona singlejob. TheNASCray-2has coordinates requests for files to be stored or achieveda peakcomputingspeedof 1720MFLOPSfor retrieved within the NPSN and maintains a direc- assembly-languagematrixmultipliesanda sus- tory of all contained files. The MSS also acts as tainedaggregate-speedin excessof 250MFLOPSfor a file server for the other NPSN subsystems, con- a jobmixof