The Cray-2 is a supercomputer with four vector processors made by Cray Research starting in 1985. At 1.9 GFLOPS peak performance, it was the fastest machine in the world when it was released, replacing the Cray X-MP in that spot. It was, in turn, replaced in that spot by the Cray Y-MP in 1988.
101-512: The Cray-2 was the first of Seymour Cray 's designs to successfully use multiple CPUs. This had been attempted in the CDC 8600 in the early 1970s, but the emitter-coupled logic (ECL) transistors of the era were too difficult to package into a working machine. The Cray-2 addressed this through the use of ECL integrated circuits , packing them in a novel 3D wiring that greatly increased circuit density. The dense packaging and resulting heat loads were
202-616: A M.Sc. in applied mathematics in 1951. In 1950, Cray joined Engineering Research Associates (ERA) in Saint Paul, Minnesota . ERA had formed out of a former United States Navy laboratory that had built codebreaking machines, a tradition ERA carried on when such work was available. ERA was introduced to computer technology during one such effort, but in other times had worked on a wide variety of basic engineering as well. Cray quickly came to be regarded as an expert on digital computer technology, especially following his design work on
303-432: A 16 KWord block of the very fastest memory possible called a Local Memory, not a cache, attaching the four background processors to it with separate high-speed pipes. This Local Memory was fed data by a dedicated foreground processor which was in turn attached to the main memory through a Gbit/s channel per CPU; X-MPs by contrast had three, for two simultaneous loads and a store and Y-MP/C-90s had five channels to avoid
404-856: A 2-D realm or coarse 3-D to a finer 3-D realm because computation did not have to rely on slow virtual memory. The Cray-2 was predominantly developed for the United States Departments of Defense and Energy . Uses tended to be for nuclear weapons research or oceanographic ( sonar ) development. However, the first Cray-2 (serial number 1) was used at the National Magnetic Fusion Energy Computer Center at Lawrence Livermore National Laboratory for unclassified energy research. It also found its way into civil agencies (such as NASA Ames Research Center ), universities, and corporations worldwide. For example, Ford and General Motors both used
505-475: A bit pattern to each character , digit , or multimedia object. Many standards exist for encoding (e.g. character encodings like ASCII , image encodings like JPEG , and video encodings like MPEG-4 ). By adding bits to each encoded unit, redundancy allows the computer to detect errors in coded data and correct them based on mathematical algorithms. Errors generally occur in low probabilities due to random bit value flipping, or "physical bit fatigue", loss of
606-475: A complete circuit, the design had plateaued. In order to gain another 10-fold increase in performance over the Cray-1, the goal Cray aimed for, the machine would have to grow more complex. So once again he turned to an 8600-like solution, doubling the clock speed through increased density, adding more of these smaller processors into the basic system, and then attempting to deal with the problem of getting heat out of
707-497: A computer a brief window of time to move information from primary volatile storage into non-volatile storage before the batteries are exhausted. Some systems, for example EMC Symmetrix , have integrated batteries that maintain volatile storage for several minutes. Utilities such as hdparm and sar can be used to measure IO performance in Linux. Full disk encryption , volume and virtual disk encryption, andor file/folder encryption
808-439: A customer reported that localized power outages had shut down their computer, but left the cooling system running — so they arrived in the morning to find the machine encased in ice. Cray addressed the problem of skew by ensuring that every signal path in his later computers was the same electrical length, so that values that were to be acted upon at a particular time were indeed all valid values. When required, he would run
909-424: A database) to represent a string of bits by a shorter bit string ("compress") and reconstruct the original string ("decompress") when needed. This utilizes substantially less storage (tens of percent) for many types of data at the cost of more computation (compress and decompress when needed). Analysis of the trade-off between storage cost saving and costs of related computations and possible delays in data availability
1010-702: A drive. When the computer has finished reading the information, the robotic arm will return the medium to its place in the library. Tertiary storage is also known as nearline storage because it is "near to online". The formal distinction between online, nearline, and offline storage is: For example, always-on spinning hard disk drives are online storage, while spinning drives that spin down automatically, such as in massive arrays of idle disks ( MAID ), are nearline storage. Removable media such as tape cartridges that can be automatically loaded, as in tape libraries , are nearline storage, while tape cartridges that must be manually loaded are offline storage. Off-line storage
1111-462: A field, which would you rather use: two strong oxen or 1024 chickens?" By the mid-1990s, this argument was becoming increasingly difficult to justify, and modern compiler technology made developing programs on such machines not much more difficult than their simpler counterparts. Cray set up a new company, SRC Computers , and started the design of his own massively parallel machine. The new design concentrated on communications and memory performance,
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#17327833766761212-465: A major problem for the Cray-2. This was solved in a unique fashion by forcing the electrically inert Fluorinert liquid through the circuitry under pressure and then cooling it outside the processor box. The unique "waterfall" cooler system came to represent high-performance computing in the public eye and was found in many informational films and as a movie prop for some time. Unlike the original Cray-1,
1313-701: A new company, Control Data Corporation . By 1960 he had completed the design of the CDC 1604 , an improved low-cost ERA 1103 that had impressive performance for its price. Even as the CDC 1604 was starting to ship to customers in 1960, Cray had already moved on to designing other computers. He first worked on the design of an upgraded version (the CDC 3000 series ), but company management wanted these machines targeted toward "business and commercial" data processing for average customers. Cray did not enjoy working on such "mundane" machines, constrained to design for low-cost construction, so CDC could sell many of them. His desire
1414-512: A new laboratory on land Cray owned in his hometown of Chippewa Falls. Part of the reason for the move may also have to do with Cray's worries about an impending nuclear war , which he felt made the Twin Cities a serious safety concern. His house, built a few hundred yards from the new CDC laboratory, included a huge bomb shelter . The new Chippewa Lab was set up during the middle of the 6600 project, although it does not seem to have delayed
1515-488: A number of unusual tales about his life away from work, termed "Rollwagenisms", from then-CEO of Cray Research, John A. Rollwagen. Cray enjoyed skiing , windsurfing , tennis , and other sports. Another favorite pastime was digging a tunnel under his home; he attributed the secret of his success to "visits by elves " while he worked in the tunnel: "While I'm digging in the tunnel, the elves will often come to me with solutions to my problem." One story has it that when Cray
1616-400: A relatively simple processor may keep state between successive computations to build up complex procedural results. Most modern computers are von Neumann machines. A modern digital computer represents data using the binary numeral system . Text, numbers, pictures, audio, and nearly any other form of information can be converted into a string of bits , or binary digits, each of which has
1717-554: A series of newer Japanese Cray-1-like machines, the Cray-2 memory system was dramatically improved, both in size as well as the number of "pipes" into the processors. When the machine was eventually delivered in 1985, the delays had been so long that much of its performance benefits were due to the faster memory. Purchasing the machine really made sense only for users with huge data sets to process. The first Cray-2 delivered possessed more physical memory (256 MWord ) than all previously delivered Cray machines combined. Simulation moved from
1818-574: A source to read instructions from, in order to start the computer. Hence, non-volatile primary storage containing a small startup program ( BIOS ) is used to bootstrap the computer, that is, to read a larger program from non-volatile secondary storage to RAM and start to execute it. A non-volatile technology used for this purpose is called ROM, for read-only memory (the terminology may be somewhat confusing as most ROM types are also capable of random access ). Many types of "ROM" are not literally read only , as updates to them are possible; however it
1919-456: A spill of the same material glistening on the floor—the joke was that if this actually occurred, the facility would have to be evacuated. The manufacturer of the liquid developed a scrubber that could be placed in line with the pump that would catalytically degrade this toxic breakdown product. Each vertical stack of logic modules sat above a stack of power modules which powered 5 volt busbars , each of which delivered about 2200 amps. The Cray-2
2020-502: A team and started on a completely new design. This lab would later close, and a decade later a new facility in Colorado Springs would open. Cray had previously attacked the problem of increased speed with three simultaneous advances: more functional units to give the system higher parallelism, tighter packaging to decrease signal delays, and faster components to allow for a higher clock speed. The classic example of this design
2121-490: A value of 0 or 1. The most common unit of storage is the byte , equal to 8 bits. A piece of information can be handled by any computer or device whose storage space is large enough to accommodate the binary representation of the piece of information , or simply data . For example, the complete works of Shakespeare , about 1250 pages in print, can be stored in about five megabytes (40 million bits) with one byte per character. Data are encoded by assigning
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#17327833766762222-427: Is a form of volatile memory that also requires the stored information to be periodically reread and rewritten, or refreshed , otherwise it would vanish. Static random-access memory is a form of volatile memory similar to DRAM with the exception that it never needs to be refreshed as long as power is applied; it loses its content when the power supply is lost. An uninterruptible power supply (UPS) can be used to give
2323-425: Is a level below secondary storage. Typically, it involves a robotic mechanism which will mount (insert) and dismount removable mass storage media into a storage device according to the system's demands; such data are often copied to secondary storage before use. It is primarily used for archiving rarely accessed information since it is much slower than secondary storage (e.g. 5–60 seconds vs. 1–10 milliseconds). This
2424-410: Is a technology consisting of computer components and recording media that are used to retain digital data . It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy , which puts fast but expensive and small storage options close to
2525-410: Is computer data storage on a medium or a device that is not under the control of a processing unit . The medium is recorded, usually in a secondary or tertiary storage device, and then physically removed or disconnected. It must be inserted or connected by a human operator before a computer can access it again. Unlike tertiary storage, it cannot be accessed without human interaction. Off-line storage
2626-408: Is done before deciding whether to keep certain data compressed or not. For security reasons , certain types of data (e.g. credit card information) may be kept encrypted in storage to prevent the possibility of unauthorized information reconstruction from chunks of storage snapshots. Generally, the lower a storage is in the hierarchy, the lesser its bandwidth and the greater its access latency
2727-609: Is estimable using S.M.A.R.T. diagnostic data that includes the hours of operation and the count of spin-ups, though its reliability is disputed. Flash storage may experience downspiking transfer rates as a result of accumulating errors, which the flash memory controller attempts to correct. The health of optical media can be determined by measuring correctable minor errors , of which high counts signify deteriorating and/or low-quality media. Too many consecutive minor errors can lead to data corruption. Not all vendors and models of optical drives support error scanning. As of 2011 ,
2828-1115: Is from the CPU. This traditional division of storage to primary, secondary, tertiary, and off-line storage is also guided by cost per bit. In contemporary usage, memory is usually fast but temporary semiconductor read-write memory , typically DRAM (dynamic RAM) or other such devices. Storage consists of storage devices and their media not directly accessible by the CPU ( secondary or tertiary storage ), typically hard disk drives , optical disc drives, and other devices slower than RAM but non-volatile (retaining contents when powered down). Historically, memory has, depending on technology, been called central memory , core memory , core storage , drum , main memory , real storage , or internal memory . Meanwhile, slower persistent storage devices have been referred to as secondary storage , external memory , or auxiliary/peripheral storage . Primary storage (also known as main memory , internal memory , or prime memory ), often referred to simply as memory ,
2929-399: Is often misattributed to Herb Grosch as so-called Grosch's law : Computers should obey a square law — when the price doubles, you should get at least four times as much speed. During this period Cray had become increasingly annoyed at what he saw as interference from CDC management. Cray always demanded an absolutely quiet work environment with a minimum of management overhead, but as
3030-416: Is primarily useful for extraordinarily large data stores, accessed without human operators. Typical examples include tape libraries and optical jukeboxes . When a computer needs to read information from the tertiary storage, it will first consult a catalog database to determine which tape or disc contains the information. Next, the computer will instruct a robotic arm to fetch the medium and place it in
3131-713: Is readily available for most storage devices. Hardware memory encryption is available in Intel Architecture, supporting Total Memory Encryption (TME) and page granular memory encryption with multiple keys (MKTME). and in SPARC M7 generation since October 2015. Distinct types of data storage have different points of failure and various methods of predictive failure analysis . Vulnerabilities that can instantly lead to total loss are head crashing on mechanical hard drives and failure of electronic components on flash storage. Impending failure on hard disk drives
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3232-491: Is slow and memory must be erased in large portions before it can be re-written. Some embedded systems run programs directly from ROM (or similar), because such programs are rarely changed. Standard computers do not store non-rudimentary programs in ROM, and rather, use large capacities of secondary storage, which is non-volatile as well, and not as costly. Recently, primary storage and secondary storage in some uses refer to what
3333-416: Is the CDC 8600 , which packed four CDC 7600 -like machines based on ECL logic into a 1 × 1 meter cylinder and ran them at an 8 ns cycle speed (125 MHz ). Unfortunately, the density needed to achieve this cycle time led to the machine's downfall. The circuit boards inside were densely packed, and since even a single malfunctioning transistor would cause an entire module to fail, packing more of them onto
3434-442: Is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in a uniform manner. Historically, early computers used delay lines , Williams tubes , or rotating magnetic drums as primary storage. By 1954, those unreliable methods were mostly replaced by magnetic-core memory . Core memory remained dominant until
3535-405: Is typically automatically fenced out, taken out of use by the device, and replaced with another functioning equivalent group in the device, where the corrected bit values are restored (if possible). The cyclic redundancy check (CRC) method is typically used in communications and storage for error detection . A detected error is then retried. Data compression methods allow in many cases (such as
3636-505: Is typically measured in milliseconds (thousandths of a second), while the access time per byte for primary storage is measured in nanoseconds (billionths of a second). Thus, secondary storage is significantly slower than primary storage. Rotating optical storage devices, such as CD and DVD drives, have even longer access times. Other examples of secondary storage technologies include USB flash drives , floppy disks , magnetic tape , paper tape , punched cards , and RAM disks . Once
3737-496: Is used to transfer information since the detached medium can easily be physically transported. Additionally, it is useful for cases of disaster, where, for example, a fire destroys the original data, a medium in a remote location will be unaffected, enabling disaster recovery . Off-line storage increases general information security since it is physically inaccessible from a computer, and data confidentiality or integrity cannot be affected by computer-based attack techniques. Also, if
3838-455: The ERA 1103 , the first commercially successful scientific computer. He remained at ERA when it was bought by Remington Rand and then Sperry Corporation in the early 1950s. At the newly formed Sperry Rand , ERA became the scientific computing arm of their UNIVAC division. Cray, along with William Norris , later became dissatisfied with ERA, then spun off as Sperry Rand. In 1957, they founded
3939-631: The University of Illinois said that Cray is "the Thomas Edison of the supercomputing industry." Cray was born in 1925 in Chippewa Falls, Wisconsin , to Seymour R. and Lillian Cray. His father was a civil engineer who fostered Cray's interest in science and engineering. As early as the age of ten he was able to build a device out of Erector Set components that converted punched paper tape into Morse code signals. The basement of
4040-476: The disk read/write head on HDDs reaches the proper placement and the data, subsequent data on the track are very fast to access. To reduce the seek time and rotational latency, data are transferred to and from disks in large contiguous blocks. Sequential or block access on disks is orders of magnitude faster than random access, and many sophisticated paradigms have been developed to design efficient algorithms based on sequential and block access. Another way to reduce
4141-423: The von Neumann bottleneck . It was the foreground processor's task to "run" the computer, handling storage and making efficient use of the multiple channels into main memory. It drove the background processors by passing in the instructions they should run via eight 16- word buffers, instead of tying up the existing cache pipes to the background processors. Modern CPUs use a variation of this design as well, although
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4242-690: The 1970s, when advances in integrated circuit technology allowed semiconductor memory to become economically competitive. This led to modern random-access memory (RAM). It is small-sized, light, but quite expensive at the same time. The particular types of RAM used for primary storage are volatile , meaning that they lose the information when not powered. Besides storing opened programs, it serves as disk cache and write buffer to improve both reading and writing performance. Operating systems borrow RAM capacity for caching so long as it's not needed by running software. Spare memory can be utilized as RAM drive for temporary high-speed data storage. As shown in
4343-501: The CPU and slower but less expensive and larger options further away. Generally, the fast technologies are referred to as "memory", while slower persistent technologies are referred to as "storage". Even the first computer designs, Charles Babbage 's Analytical Engine and Percy Ludgate 's Analytical Machine, clearly distinguished between processing and memory (Babbage stored numbers as rotations of gears, while Ludgate stored numbers as displacements of rods in shuttles). This distinction
4444-625: The Cray-2 for processing complex Finite Element Analysis models of car bodyshells, and for performing virtual crash testing of bodyshell components prior to production. The Cray-2 would have been superseded by the Cray-3 , but due to development problems only a single Cray-3 was built and it was never paid for. The spiritual descendant of the Cray-2 is the Cray X1 , offered by Cray . In 2012, Piotr Luszczek (a former doctoral student of Jack Dongarra ), presented results showing that an iPad 2 matched
4545-568: The Cray-2 had difficulties delivering peak performance. Other machines from the company, like the X-MP and Y-MP, outsold the Cray-2 by a wide margin. When Cray began development of the Cray-3 , the company chose to develop the Cray C90 series instead. This is the same sequence of events that occurred when the 8600 was being developed, and as in that case, Cray left the company. With the successful launch of his famed Cray-1 , Seymour Cray turned to
4646-521: The Cray-2 was 150–200 kW. Research conducted at the Lawrence Livermore National Laboratory in the early 1990s indicated that to a limited extent the perfluorinated polyether used to cool Cray-2 circuits would break down to form the extremely toxic gas perfluoroisobutylene . At the time, Cray had created a poster showing the transparent "bubble chamber" that the cooling fluid was run through for visual effect, with
4747-472: The Cray-3 project from Chippewa Falls to a laboratory in Colorado Springs, Colorado . In 1989, Cray was faced with a repeat of history when the Cray-3 started to run into difficulties. An upgrade of the X-MP using high-speed memory from the Cray-2 was under development and seemed to be making real progress, and once again management was faced with two projects and limited budgets. They eventually decided to take
4848-493: The Cray-3, and the ending of the Cold War made it unlikely anyone would buy enough Cray-4s to offer a return on the development funds. The company ran out of money and filed for Chapter 11 bankruptcy 24 March 1995. Cray had always resisted the massively parallel solution to high-speed computing, offering a variety of reasons that it would never work as well as one very fast processor. He famously quipped "If you were plowing
4949-511: The I/O bottleneck is to use multiple disks in parallel to increase the bandwidth between primary and secondary memory. Secondary storage is often formatted according to a file system format, which provides the abstraction necessary to organize data into files and directories , while also providing metadata describing the owner of a certain file, the access time, the access permissions, and other information. Most computer operating systems use
5050-449: The ICs' small size. Although IC design continued to improve, the physical size of the ICs was constrained largely by mechanical limits; the resulting component had to be large enough to solder into a system. Dramatic improvements in density were possible, as the rapid improvement in microprocessor design was showing, but for the type of ICs used by Cray, ones representing a very small part of
5151-853: The June plan. There have been no significant changes or deviations from the June plan." Cray was mortally wounded in a rollover accident caused by a reckless driver while Cray was merging his Jeep Cherokee onto Interstate 25 , near the Air Force Academy in Colorado. Cray died of his injuries on October 5, 1996, two weeks after the accident and one week after his 71st birthday. The IEEE Computer Society 's Seymour Cray Computer Engineering Award , established in late 1997, recognizes innovative contributions to high performance computing systems exemplifying Cray's creative spirit. Main memory Computer data storage or digital data storage
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#17327833766765252-525: The X-MP, largely due to very fast and large main memory, and thus it sold in much smaller numbers. The Cray-2 ran at 250 MHz with a very deep pipeline , making it harder to write code than for the shorter-pipe X-MP. As the Cray-3 project started, he found himself once again being "bothered" too much with day-to-day tasks. In order to concentrate on design, Cray left the CEO position of Cray Research in 1980 to become an independent contractor. In 1988, he moved
5353-516: The bottleneck that hampered many parallel designs. Design had just started when Cray was killed in a car accident. SRC Computers carried on development and specialized in reconfigurable computing . Cray frequently cited two important aspects to his design philosophy: remove heat, and ensure that all signals that are supposed to arrive somewhere at the same time do indeed arrive at the same time. His computers were equipped with built-in cooling systems, extending ultimately to coolant channels cast into
5454-468: The cards greatly increased the chance of failure. Cooling the closely packed individual components also represented a major challenge. One solution to this problem, one that most computer vendors had already moved to, was to use integrated circuits (ICs) instead of individual components. Each IC included a selection of components from a module pre-wired into a circuit by the automated construction process. If an IC did not work, another one would be tried. At
5555-584: The company grew he found himself constantly interrupted by middle managers who – according to Cray – did little but gawk and use him as a sales tool by introducing him to prospective customers. Cray decided that in order to continue development he would have to move from St. Paul, far enough that it would be too long a drive for a "quick visit" and long-distance telephone charges would be just enough to deter most calls, yet close enough that real visits or board meetings could be attended without too much difficulty. After some debate, Norris backed him and set up
5656-511: The company while they were being designed. The 8600 was running into similar difficulties and Cray eventually decided that the only solution was to start over fresh. This time Norris was not willing to take the risk, and another project within the company, the CDC STAR-100 , seemed to be progressing more smoothly. Norris said he was willing to keep the project alive at a low level until the STAR
5757-524: The concept of virtual memory , allowing the utilization of more primary storage capacity than is physically available in the system. As the primary memory fills up, the system moves the least-used chunks ( pages ) to a swap file or page file on secondary storage, retrieving them later when needed. If a lot of pages are moved to slower secondary storage, the system performance is degraded. The secondary storage, including HDD , ODD and SSD , are usually block-addressable. Tertiary storage or tertiary memory
5858-417: The density was still not enough to reach their performance goals. Teams worked on the design for about two years before even Cray himself "gave up" and decided it would be best if they simply canceled the project and fired everyone working on it. Les Davis, Cray's former design collaborator who had remained at Cray headquarters, decided it should be continued at low priority. After some minor personnel movements,
5959-631: The design of its successor. By 1979 he had become fed up with management interruptions in what was now a large company, and as he had done in the past, decided to resign his management post and move to form a new lab. As with his original move to Chippewa Falls, Wisconsin from Control Data HQ in Minneapolis, Minnesota , Cray management understood his needs and supported his move to a new lab in Boulder, Colorado . Working as an independent consultant at these new Cray Labs, starting in 1980 he put together
6060-430: The desired data to primary storage. Secondary storage is non-volatile (retaining data when its power is shut off). Modern computer systems typically have two orders of magnitude more secondary storage than primary storage because secondary storage is less expensive. In modern computers, hard disk drives (HDDs) or solid-state drives (SSDs) are usually used as secondary storage. The access time per byte for HDDs or SSDs
6161-494: The desired location of data. Then it reads or writes the data in the memory cells using the data bus. Additionally, a memory management unit (MMU) is a small device between CPU and RAM recalculating the actual memory address, for example to provide an abstraction of virtual memory or other tasks. As the RAM types used for primary storage are volatile (uninitialized at start up), a computer containing only such storage would not have
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#17327833766766262-400: The diagram, traditionally there are two more sub-layers of the primary storage, besides main large-capacity RAM: Main memory is directly or indirectly connected to the central processing unit via a memory bus . It is actually two buses (not on the diagram): an address bus and a data bus . The CPU firstly sends a number through an address bus, a number called memory address , that indicates
6363-628: The family home was given over to the young Cray as a "laboratory". Cray graduated from Chippewa Falls High School in 1943 before being drafted for World War II as a radio operator. He saw action in Europe , and then moved to the Pacific theatre where he worked on breaking Japanese naval codes . On his return to the United States he earned a B.Sc. in electrical engineering at the University of Minnesota , graduating in 1949, followed by
6464-441: The first commercial supercomputer, outperforming everything then available by a wide margin. While expensive, for those that needed the fastest computer available there was nothing else on the market that could compete. When other companies (namely IBM ) attempted to create machines with similar performance, they stumbled ( IBM 7030 Stretch ). In the 6600, Cray had solved the critical design problem of "imprecise interrupts", which
6565-443: The foreground processor is now referred to as the load/store unit and is not a complete machine unto its own. Main memory banks were arranged in quadrants to be accessed at the same time, allowing programmers to scatter their data across memory to gain higher parallelism. The downside to this approach is that the cost of setting up the scatter/gather unit in the foreground processor was fairly high. Stride conflicts corresponding to
6666-477: The former using standard MOSFETs and the latter using floating-gate MOSFETs . In modern computers, primary storage almost exclusively consists of dynamic volatile semiconductor random-access memory (RAM), particularly dynamic random-access memory (DRAM). Since the turn of the century, a type of non-volatile floating-gate semiconductor memory known as flash memory has steadily gained share as off-line storage for home computers. Non-volatile semiconductor memory
6767-486: The historical performance of the Cray-2 on an embedded LINPACK benchmark. Due to the use of liquid cooling, the Cray-2 was given the nickname "Bubbles", and common jokes around the computer made reference to this unique system. Gags included "No Fishing" signs, cardboard depictions of the Loch Ness Monster rising out of the heat exchanger tank, plastic fish inside the exchanger, etc. The power consumption of
6868-568: The information stored for archival purposes is rarely accessed, off-line storage is less expensive than tertiary storage. In modern personal computers, most secondary and tertiary storage media are also used for off-line storage. Optical discs and flash memory devices are the most popular, and to a much lesser extent removable hard disk drives; older examples include floppy disks and Zip disks. In enterprise uses, magnetic tape cartridges are predominant; older examples include open-reel magnetic tape and punched cards. Storage technologies at all levels of
6969-399: The machine in an attempt to enable it to run as fast as possible. Unlike most high-end projects, Cray realized that there was considerably more to performance than simple processor speed, that I/O bandwidth had to be maximized as well in order to avoid "starving" the processor of data to crunch. He later noted, "Anyone can build a fast CPU. The trick is to build a fast system." The 6600 was
7070-468: The machine would have to be built using gallium arsenide semiconductors. In the past Cray had always avoided using anything even near the state of the art , preferring to use well-known solutions and designing a fast machine based on them. In this case, Cray was developing every part of the machine, even the chips inside it. Nevertheless, the team were able to get the machine working and delivered their first example to NCAR on 24 May 1993. The machine
7171-408: The machine. Another design problem was the increasing performance gap between the processor and main memory . In the era of the CDC 6600 memory ran at the same speed as the processor, and the main problem was feeding data into it. Cray solved this by adding ten smaller computers to the system, allowing them to deal with the slower external storage (disks and tapes) and "squirt" data into memory when
7272-487: The main processor was busy. This solution no longer offered any advantages; memory was large enough that entire data sets could be read into it, but the processors ran so much faster than memory that they would often spend long times waiting for data to arrive. Adding four processors simply made this problem worse. To avoid this problem the new design banked memory and two sets of registers (the B- and T-registers) were replaced with
7373-408: The mainframes and thermally coupled to metal plates within the circuit boards, and to systems immersed in coolants. In a story he told about himself, he realized early in his career that he should interlock the computers with the cooling systems so that the computers would not operate unless the cooling systems were operational. It did not originally occur to him to interlock in the other direction until
7474-641: The most commonly used data storage media are semiconductor, magnetic, and optical, while paper still sees some limited usage. Some other fundamental storage technologies, such as all-flash arrays (AFAs) are proposed for development. Semiconductor memory uses semiconductor -based integrated circuit (IC) chips to store information. Data are typically stored in metal–oxide–semiconductor (MOS) memory cells . A semiconductor memory chip may contain millions of memory cells, consisting of tiny MOS field-effect transistors (MOSFETs) and/or MOS capacitors . Both volatile and non-volatile forms of semiconductor memory exist,
7575-496: The number of memory banks suffered a performance penalty (latency) as occasionally happened in power-of-2 FFT-based algorithms. As the Cray 2 had a much larger memory than Cray 1s or X-MPs, this problem was easily rectified by adding an extra unused element to an array to spread the work out. Early Cray-2 models soon settled on a design using large circuit boards packed with ICs. This made them extremely difficult to solder together, and
7676-408: The physical bit in the storage of its ability to maintain a distinguishable value (0 or 1), or due to errors in inter or intra-computer communication. A random bit flip (e.g. due to random radiation ) is typically corrected upon detection. A bit or a group of malfunctioning physical bits (the specific defective bit is not always known; group definition depends on the specific storage device)
7777-544: The processor. When it was released it easily beat almost every machine in terms of speed, including the STAR-100 that had beaten the 8600 for funding. The only machine able to perform on the same sort of level was the ILLIAC IV , a specialized one-off machine that rarely operated near its maximum performance, except on very specific tasks. In general, the Cray-1 beat anything on the market by a wide margin. Serial number 001
7878-469: The project. After the 6600 shipped, the successor CDC 7600 system was the next product to be developed in Chippewa Falls, offering peak computational speeds of ten times the 6600. The failed follow-on to the 7600, the CDC 8600 , was the project that finally ended his run of successes at CDC in 1972. Although the 6600 and 7600 had been huge successes in the end, both projects had almost bankrupted
7979-530: The result. It would have to be reconfigured to change its behavior. This is acceptable for devices such as desk calculators , digital signal processors , and other specialized devices. Von Neumann machines differ in having a memory in which they store their operating instructions and data. Such computers are more versatile in that they do not need to have their hardware reconfigured for each new program, but can simply be reprogrammed with new in-memory instructions; they also tend to be simpler to design, in that
8080-442: The resulting stack was only about 30 mm high. With this sort of density there was no way any conventional air-cooled system would work; there was too little room for air to flow between the ICs. Instead the system would be immersed in a tank of a new inert liquid from 3M , Fluorinert . The cooling liquid was forced sideways through the modules under pressure, and the flow rate was roughly one inch per second. The heated liquid
8181-522: The safer route, releasing the new design as the Cray Y-MP . Cray decided to spin off the Colorado Springs laboratory to form Cray Computer Corporation . This new entity took the Cray-3 project with them. The 500 MHz Cray-3 proved to be Cray's second major failure. In order to provide the tenfold increase in performance that he always demanded of his newest machines, Cray decided that
8282-413: The storage hierarchy can be differentiated by evaluating certain core characteristics as well as measuring characteristics specific to a particular implementation. These core characteristics are volatility, mutability, accessibility, and addressability. For any particular implementation of any storage technology, the characteristics worth measuring are capacity and performance. Non-volatile memory retains
8383-422: The stored information even if not constantly supplied with electric power. It is suitable for long-term storage of information. Volatile memory requires constant power to maintain the stored information. The fastest memory technologies are volatile ones, although that is not a universal rule. Since the primary storage is required to be very fast, it predominantly uses volatile memory. Dynamic random-access memory
8484-479: The supercomputer industry. Joel S. Birnbaum , then chief technology officer of Hewlett-Packard , said of him: "It seems impossible to exaggerate the effect he had on the industry; many of the things that high performance computers now do routinely were at the farthest edge of credibility when Seymour envisioned them." Larry Smarr , then director of the National Center for Supercomputing Applications at
8585-460: The team continued on much as before. Six months later Cray had his " eureka " moment. He called the main engineers together for a meeting and presented a new solution to the problem. Instead of making one larger circuit board, each "card" would instead consist of a 3-D stack of eight, connected together in the middle of the boards using pins sticking up from the surface (known as "pogos" or "z-pins"). The cards were packed right on top of each other, so
8686-458: The time the 8600 was being designed the simple MOSFET -based technology did not offer the speed Cray needed. Relentless improvements changed things by the mid-1970s, however, and the Cray-1 had been able to use newer ICs and still run at a respectable 12.5 ns (80 MHz). In fact, the Cray-1 was actually somewhat faster than the 8600 because it packed considerably more logic into the system due to
8787-470: The traces back and forth on the circuit boards until the desired length was achieved, and he employed Maxwell's equations in design of the boards to ensure that any radio frequency effects which altered the signal velocity and hence the electrical path length were accounted for. When asked what kind of CAD tools he used to design computers, Cray said that he liked pads of 8 1 ⁄ 2 ″ × 11″ "faintly-ruled 1 ⁄ 4 -inch quadrille " paper. Cray
8888-408: Was "lent" to Los Alamos National Laboratory in 1976, and that summer the first full system was sold to the National Center for Atmospheric Research (NCAR) for $ 8.8 million. The company's early estimates had suggested that they might sell a dozen such machines, based on sales of similar machines from the CDC era, so the price was set accordingly. Eventually, well over 80 Cray-1s were sold, the company
8989-473: Was a huge success financially, and Cray's innovations with super computers won him the nickname "The Wizard of Chippewa Falls". Follow-up success was not as easy. While he worked on the Cray-2 , other teams delivered the two-processor Cray X-MP , which was another huge success and later the four-processor X-MP. When the Cray-2 was finally released after six years of development it was only marginally faster than
9090-468: Was also in Chippewa Falls. At first there was some question as to what exactly the new company should do. It did not seem that there would be any way for them to afford to develop a new computer, given that the now-large CDC had been unable to support more than one. When the President in charge of financing traveled to Wall Street to look for seed money , he was surprised to find that Cray's reputation
9191-405: Was asked by management to provide detailed one-year and five-year plans for his next machine, he simply wrote, "Five-year goal: Build the biggest computer in the world. One year goal: One-fifth of the above." And another time, when expected to write a multi-page detailed status report for the company executives, Cray's two-sentence report read: "Activity is progressing satisfactorily as outlined under
9292-472: Was cooled using chilled water heat exchangers and returned to the main tank. Work on the new design started in earnest in 1982, several years after the original start date. While this was going on the Cray X-MP was being developed under the direction of Steve Chen at Cray headquarters, and looked like it would give the Cray-2 a serious run for its money. In order to address this internal threat, as well as
9393-525: Was delivered, at which point full funding could be put into the 8600. Cray was unwilling to work under these conditions and left the company. The split was fairly amicable, and when he started Cray Research in a new laboratory on the same Chippewa property a year later, Norris invested $ 250,000 in start-up money. Like CDC's organization, Cray R&D was based in Chippewa Falls and business headquarters were in Minneapolis. Unlike CDC, Cray's manufacturing
9494-467: Was extended in the Von Neumann architecture , where the CPU consists of two main parts: The control unit and the arithmetic logic unit (ALU). The former controls the flow of data between the CPU and memory, while the latter performs arithmetic and logical operations on data. Without a significant amount of memory, a computer would merely be able to perform fixed operations and immediately output
9595-441: Was historically called, respectively, secondary storage and tertiary storage . The primary storage, including ROM , EEPROM , NOR flash , and RAM , are usually byte-addressable . Secondary storage (also known as external memory or auxiliary storage ) differs from primary storage in that it is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfer
9696-498: Was involved in the design of the following computers: Cray married Verene Voll in 1947. They had known each other since childhood. She was the daughter of a Methodist minister, as was Cray's mother, and Verene worked as a nutritionist. They had three children. Cray and Voll divorced around 1978. He later married Geri M. Harrand. Cray was the grandfather of the LGBTQ rights activist Andrew Cray . Cray avoided publicity. There are
9797-447: Was largely responsible for IBM's failure. He did this by replacing I/O interrupts with a polled request issued by one of ten so-called peripheral processors, which were built-in mini-computers that did all transfers in and out of the 6600's central memory. The following CDC 7600 even improved the speed advantage by a factor of five. In 1963, in a Business Week article announcing the CDC 6600, Seymour Cray clearly expressed an idea that
9898-456: Was powered by two motor-generators, which took in 480 V three-phase . Seymour Cray Seymour Roger Cray (September 28, 1925 – October 5, 1996 ) was an American electrical engineer and supercomputer architect who designed a series of computers that were the fastest in the world for decades, and founded Cray Research , which built many of these machines. Called "the father of supercomputing", Cray has been credited with creating
9999-486: Was still essentially a prototype, and the company was using the installation to debug the design. By this time a number of massively parallel machines were coming into the market at price/performance ratios the Cray-3 could not touch. Cray responded through "brute force", starting design of the Cray-4 , which would run at 1 GHz and outpower these machines, regardless of price. In 1995 there had been no further sales of
10100-404: Was to "produce the largest [fastest] computer in the world". So after some basic design work on the CDC 3000 series, he turned that over to others and went on to work on the CDC 6600 . Nonetheless, several special features of the 6600 first started to appear in the 3000 series. Although in terms of hardware the 6600 was not on the leading edge, Cray invested considerable effort into the design of
10201-399: Was very well known. Far from struggling for some role to play in the market, the financial world was more than willing to provide Cray with all the money they would need to develop a new machine. After several years of development, their first product was released in 1976 as the Cray-1 . As with earlier Cray designs, the Cray-1 made sure that the entire computer was fast, as opposed to just
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