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64-570: BESM (БЭСМ) is the series of Soviet mainframe computers built in 1950–60s. The name is an acronym for "Bolshaya (or Bystrodeystvuyushchaya) Elektronno-schotnaya Mashina" ("Большая электронно-счётная машина" or "Быстродействующая электронно-счётная машина"), meaning "Big Electronic Computing Machine" or "High-Speed Electronic Computing Machine". It was designed at the Institute of Precision Mechanics and Computer Engineering The BESM series included six models. BESM-1 , originally referred to as simply

128-558: A mainframe or big iron , is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses , industry and consumer statistics , enterprise resource planning , and large-scale transaction processing . A mainframe computer is large but not as large as a supercomputer and has more processing power than some other classes of computers, such as minicomputers , servers , workstations , and personal computers . Most large-scale computer-system architectures were established in

192-462: A constant failure rate λ {\displaystyle \lambda } implies that T {\displaystyle T} has an exponential distribution with parameter λ {\displaystyle \lambda } . Since the MTBF is the expected value of T {\displaystyle T} , it is given by the reciprocal of the failure rate of the system, Once

256-489: A dangerous condition. It can be calculated as follows: where B 10 is the number of operations that a device will operate prior to 10% of a sample of those devices would fail and n op is number of operations. B 10d is the same calculation, but where 10% of the sample would fail to danger. n op is the number of operations/cycle in one year. In fact the MTBF counting only failures with at least some systems still operating that have not yet failed underestimates

320-449: A fraction of the acquisition price and offer local users much greater control over their own systems given the IT policies and practices at that time. Terminals used for interacting with mainframe systems were gradually replaced by personal computers . Consequently, demand plummeted and new mainframe installations were restricted mainly to financial services and government. In the early 1990s, there

384-539: A level of sophistication not usually available with most server solutions. Modern mainframes, notably the IBM Z servers, offer two levels of virtualization : logical partitions ( LPARs , via the PR/SM facility) and virtual machines (via the z/VM operating system). Many mainframe customers run two machines: one in their primary data center and one in their backup data center —fully active, partially active, or on standby—in case there

448-607: A more proactive maintenance approach. This synergy allows for the identification of patterns and potential failures before they occur, enabling preventive maintenance and reducing unplanned downtime. As a result, MTBF becomes a key performance indicator (KPI) within TPM, guiding decisions on maintenance schedules, spare parts inventory, and ultimately, optimizing the lifespan and efficiency of machinery. This strategic use of MTBF within TPM frameworks enhances overall production efficiency, reduces costs associated with breakdowns, and contributes to

512-420: A product's MTBF according to various methods and standards (MIL-HDBK-217F, Telcordia SR332, Siemens SN 29500, FIDES, UTE 80-810 (RDF2000), etc.). The Mil-HDBK-217 reliability calculator manual in combination with RelCalc software (or other comparable tool) enables MTBF reliability rates to be predicted based on design. A concept which is closely related to MTBF, and is important in the computations involving MTBF,

576-432: A quantitative identity between working and failed units. Since MTBF can be expressed as “average life (expectancy)”, many engineers assume that 50% of items will have failed by time t = MTBF. This inaccuracy can lead to bad design decisions. Furthermore, probabilistic failure prediction based on MTBF implies the total absence of systematic failures (i.e., a constant failure rate with only intrinsic, random failures), which

640-434: A reference to the anticipated Year 2000 problem (Y2K). That trend started to turn around in the late 1990s as corporations found new uses for their existing mainframes and as the price of data networking collapsed in most parts of the world, encouraging trends toward more centralized computing. The growth of e-business also dramatically increased the number of back-end transactions processed by mainframe software as well as

704-407: A single mainframe can replace higher-functioning hardware services available to conventional servers . While mainframes pioneered this capability, virtualization is now available on most families of computer systems, though not always to the same degree or level of sophistication. Mainframes can add or hot swap system capacity without disrupting system function, with specificity and granularity to

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768-500: A system out of two serial components can be calculated as: and for a system out of two parallel components MDT can be calculated as: Through successive application of these four formulae, the MTBF and MDT of any network of repairable components can be computed, provided that the MTBF and MDT is known for each component. In a special but all-important case of several serial components, MTBF calculation can be easily generalised into which can be shown by induction, and likewise since

832-732: Is a catastrophe affecting the first building. Test, development, training, and production workload for applications and databases can run on a single machine, except for extremely large demands where the capacity of one machine might be limiting. Such a two-mainframe installation can support continuous business service, avoiding both planned and unplanned outages. In practice, many customers use multiple mainframes linked either by Parallel Sysplex and shared DASD (in IBM's case), or with shared, geographically dispersed storage provided by EMC or Hitachi. Mainframes are designed to handle very high volume input and output (I/O) and emphasize throughput computing. Since

896-450: Is also spurring major mainframe investments to solve exceptionally difficult computing problems, e.g. providing unified, extremely high volume online transaction processing databases for 1 billion consumers across multiple industries (banking, insurance, credit reporting, government services, etc.) In late 2000, IBM introduced 64-bit z/Architecture , acquired numerous software companies such as Cognos and introduced those software products to

960-634: Is being refreshed. In the late 1950s, mainframes had only a rudimentary interactive interface (the console) and used sets of punched cards , paper tape , or magnetic tape to transfer data and programs. They operated in batch mode to support back office functions such as payroll and customer billing, most of which were based on repeated tape-based sorting and merging operations followed by line printing to preprinted continuous stationery . When interactive user terminals were introduced, they were used almost exclusively for applications (e.g. airline booking ) rather than program development. However, in 1961

1024-757: Is dependent on its ability to scale, support mixed workloads, reduce labor costs, deliver uninterrupted service for critical business applications, and several other risk-adjusted cost factors. Mainframes also have execution integrity characteristics for fault tolerant computing. For example, z900, z990, System z9, and System z10 servers effectively execute result-oriented instructions twice, compare results, arbitrate between any differences (through instruction retry and failure isolation), then shift workloads "in flight" to functioning processors, including spares, without any impact to operating systems, applications, or users. This hardware-level feature, also found in HP's NonStop systems,

1088-421: Is known as lock-stepping, because both processors take their "steps" (i.e. instructions) together. Not all applications absolutely need the assured integrity that these systems provide, but many do, such as financial transaction processing. IBM , with the IBM Z series, continues to be a major manufacturer in the mainframe market. In 2000, Hitachi co-developed the zSeries z900 with IBM to share expenses, and

1152-400: Is not easy to verify. Assuming no systematic errors, the probability the system survives during a duration, T, is calculated as exp^(-T/MTBF). Hence the probability a system fails during a duration T, is given by 1 - exp^(-T/MTBF). MTBF value prediction is an important element in the development of products. Reliability engineers and design engineers often use reliability software to calculate

1216-431: Is particularly significant in the context of total productive maintenance (TPM), a comprehensive maintenance strategy aimed at maximizing equipment effectiveness . MTBF provides a quantitative measure of the time elapsed between failures of a system during normal operation, offering insights into the reliability and performance of manufacturing equipment. By integrating MTBF with TPM principles, manufacturers can achieve

1280-478: Is the mean down time (MDT). MDT can be defined as mean time which the system is down after the failure. Usually, MDT is considered different from MTTR (Mean Time To Repair); in particular, MDT usually includes organizational and logistical factors (such as business days or waiting for components to arrive) while MTTR is usually understood as more narrow and more technical. MTBF serves as a crucial metric for managing machinery and equipment reliability. Its application

1344-630: Is the expected value of the random variable T {\displaystyle T} indicating the time until failure. Thus, it can be written as where f T ( t ) {\displaystyle f_{T}(t)} is the probability density function of T {\displaystyle T} . Equivalently, the MTBF can be expressed in terms of the reliability function R T ( t ) {\displaystyle R_{T}(t)} as The MTBF and T {\displaystyle T} have units of time (e.g., hours). Any practically-relevant calculation of

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1408-452: Is the instantaneous time it went down, which is after (i.e. greater than) the moment it went up, the "up time". The difference ("down time" minus "up time") is the amount of time it was operating between these two events. By referring to the figure above, the MTBF of a component is the sum of the lengths of the operational periods divided by the number of observed failures: In a similar manner, mean down time (MDT) can be defined as The MTBF

1472-447: Is the network in which the components are arranged in parallel, and P F ( c , t ) {\displaystyle PF(c,t)} is the probability of failure of component c {\displaystyle c} during "vulnerability window" t {\displaystyle t} . Intuitively, both these formulae can be explained from the point of view of failure probabilities. First of all, let's note that

1536-2186: Is the network in which the components are arranged in series. For the network containing parallel repairable components, to find out the MTBF of the whole system, in addition to component MTBFs, it is also necessary to know their respective MDTs. Then, assuming that MDTs are negligible compared to MTBFs (which usually stands in practice), the MTBF for the parallel system consisting from two parallel repairable components can be written as follows: mtbf ( c 1 ∥ c 2 ) = 1 1 mtbf ( c 1 ) × PF ( c 2 , mdt ( c 1 ) ) + 1 mtbf ( c 2 ) × PF ( c 1 , mdt ( c 2 ) ) = 1 1 mtbf ( c 1 ) × mdt ( c 1 ) mtbf ( c 2 ) + 1 mtbf ( c 2 ) × mdt ( c 2 ) mtbf ( c 1 ) = mtbf ( c 1 ) × mtbf ( c 2 ) mdt ( c 1 ) + mdt ( c 2 ) , {\displaystyle {\begin{aligned}{\text{mtbf}}(c_{1}\parallel c_{2})&={\frac {1}{{\frac {1}{{\text{mtbf}}(c_{1})}}\times {\text{PF}}(c_{2},{\text{mdt}}(c_{1}))+{\frac {1}{{\text{mtbf}}(c_{2})}}\times {\text{PF}}(c_{1},{\text{mdt}}(c_{2}))}}\\[1em]&={\frac {1}{{\frac {1}{{\text{mtbf}}(c_{1})}}\times {\frac {{\text{mdt}}(c_{1})}{{\text{mtbf}}(c_{2})}}+{\frac {1}{{\text{mtbf}}(c_{2})}}\times {\frac {{\text{mdt}}(c_{2})}{{\text{mtbf}}(c_{1})}}}}\\[1em]&={\frac {{\text{mtbf}}(c_{1})\times {\text{mtbf}}(c_{2})}{{\text{mdt}}(c_{1})+{\text{mdt}}(c_{2})}}\;,\end{aligned}}} where c 1 ∥ c 2 {\displaystyle c_{1}\parallel c_{2}}

1600-493: The Telum . Unisys produces code compatible mainframe systems that range from laptops to cabinet-sized mainframes that use homegrown CPUs as well as Xeon processors. Furthermore, there exists a market for software applications to manage the performance of mainframe implementations. In addition to IBM, significant market competitors include BMC and Precisely ; former competitors include Compuware and CA Technologies . Starting in

1664-684: The 1960s, but they continue to evolve. Mainframe computers are often used as servers. The term mainframe was derived from the large cabinet, called a main frame , that housed the central processing unit and main memory of early computers. Later, the term mainframe was used to distinguish high-end commercial computers from less powerful machines. Modern mainframe design is characterized less by raw computational speed and more by: The high stability and reliability of mainframes enable these machines to run uninterrupted for very long periods of time, with mean time between failures (MTBF) measured in decades. Mainframes have high availability , one of

1728-504: The 1980s, many mainframes supported general purpose graphic display terminals, and terminal emulation, but not graphical user interfaces. This form of end-user computing became obsolete in the 1990s due to the advent of personal computers provided with GUIs . After 2000, modern mainframes partially or entirely phased out classic " green screen " and color display terminal access for end-users in favour of Web-style user interfaces. The infrastructure requirements were drastically reduced during

1792-595: The 2010s, cloud computing is now a less expensive, more scalable alternative. Several manufacturers and their successors produced mainframe computers from the 1950s until the early 21st century, with gradually decreasing numbers and a gradual transition to simulation on Intel chips rather than proprietary hardware. The US group of manufacturers was first known as " IBM and the Seven Dwarfs ": usually Burroughs , UNIVAC , NCR , Control Data , Honeywell , General Electric and RCA , although some lists varied. Later, with

1856-890: The 64-bit IBM Z CMOS servers have nothing physically in common with the older systems. Notable manufacturers outside the US were Siemens and Telefunken in Germany , ICL in the United Kingdom , Olivetti in Italy, and Fujitsu , Hitachi , Oki , and NEC in Japan . The Soviet Union and Warsaw Pact countries manufactured close copies of IBM mainframes during the Cold War ; the BESM series and Strela are examples of independently designed Soviet computers. Elwro in Poland

1920-546: The BESM or BESM AN ("BESM Akademii Nauk", BESM of the Academy of Sciences), was completed in 1952. Only one BESM-1 machine was built. The machine used approximately 5,000 vacuum tubes . At the time of completion, it was the fastest computer in Europe. The floating-point numbers were represented as 39-bit words : 32 bits for the mantissa , one bit for sign, and 1 + 5 bits for the exponent. It

1984-542: The Japanese market. The amount of vendor investment in mainframe development varies with market share. Fujitsu and Hitachi both continue to use custom S/390-compatible processors, as well as other CPUs (including POWER and Xeon) for lower-end systems. Bull uses a mixture of Itanium and Xeon processors. NEC uses Xeon processors for its low-end ACOS-2 line, but develops the custom NOAH-6 processor for its high-end ACOS-4 series. IBM also develops custom processors in-house, such as

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2048-417: The MTBF assumes that the system is working within its "useful life period", which is characterized by a relatively constant failure rate (the middle part of the " bathtub curve ") when only random failures are occurring. In other words, it is assumed that the system has survived initial setup stresses and has not yet approached its expected end of life, both of which often increase the failure rate. Assuming

2112-415: The MTBF by failing to include in the computations the partial lifetimes of the systems that have not yet failed. With such lifetimes, all we know is that the time to failure exceeds the time they've been running. This is called censoring . In fact with a parametric model of the lifetime, the likelihood for the experience on any given day is as follows : where For a constant exponential distribution ,

2176-403: The MTBF of a system is known, and assuming a constant failure rate, the probability that any one particular system will be operational for a given duration can be inferred from the reliability function of the exponential distribution , R T ( t ) = e − λ t {\displaystyle R_{T}(t)=e^{-\lambda t}} . In particular,

2240-524: The back-office engines behind the world's financial markets and much of global commerce". As of 2010 , while mainframe technology represented less than 3% of IBM's revenues, it "continue[d] to play an outsized role in Big Blue's results". IBM has continued to launch new generations of mainframes: the IBM z13 in 2015, the z14 in 2017, the z15 in 2019, and the z16 in 2022, the latter featuring among other things an "integrated on-chip AI accelerator" and

2304-536: The beginning of the series release was in 1964. EPSILON (a macro language with high-level features including strings and lists, developed by Andrey Ershov at Novosibirsk in 1967) was used to implement ALGOL 68 on the M-220. The BESM-6 was the best-known and most influential model of the series. The design was completed in 1965. Production started in 1968 and continued for the following 19 years. Mainframe computer A mainframe computer , informally called

2368-411: The components. With parallel components the situation is a bit more complicated: the whole system will fail if and only if after one of the components fails, the other component fails while the first component is being repaired; this is where MDT comes into play: the faster the first component is repaired, the less is the "vulnerability window" for the other component to fail. Using similar logic, MDT for

2432-423: The continuous improvement of manufacturing processes. Two components c 1 , c 2 {\displaystyle c_{1},c_{2}} (for instance hard drives, servers, etc.) may be arranged in a network, in series or in parallel . The terminology is here used by close analogy to electrical circuits, but has a slightly different meaning. We say that the two components are in series if

2496-592: The departure of General Electric and RCA, it was referred to as IBM and the BUNCH . IBM's dominance grew out of their 700/7000 series and, later, the development of the 360 series mainframes. The latter architecture has continued to evolve into their current zSeries mainframes which, along with the then Burroughs and Sperry (now Unisys ) MCP -based and OS1100 mainframes, are among the few mainframe architectures still extant that can trace their roots to this early period. While IBM's zSeries can still run 24-bit System/360 code,

2560-496: The different technologies and architectures for supercomputers and mainframes has led to a so-called gameframe . Mean time between failures The definition of MTBF depends on the definition of what is considered a failure. For complex, repairable systems, failures are considered to be those out of design conditions which place the system out of service and into a state for repair. Failures which occur that can be left or maintained in an unrepaired condition, and do not place

2624-558: The early 1990s, many supercomputers were based on a mainframe architecture with supercomputing extensions. An example of such a system is the HITAC S-3800 , which was instruction-set compatible with IBM System/370 mainframes, and could run the Hitachi VOS3 operating system (a fork of IBM MVS ). The S-3800 therefore can be seen as being both simultaneously a supercomputer and also an IBM-compatible mainframe. In 2007, an amalgamation of

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2688-431: The failure of either causes the failure of the network, and that they are in parallel if only the failure of both causes the network to fail. The MTBF of the resulting two-component network with repairable components can be computed according to the following formulae, assuming that the MTBF of both individual components is known: where c 1 ; c 2 {\displaystyle c_{1};c_{2}}

2752-450: The failure of the FM radio does not prevent the primary operation of the vehicle. It is recommended to use Mean time to failure (MTTF) instead of MTBF in cases where a system is replaced after a failure ("non-repairable system"), since MTBF denotes time between failures in a system which can be repaired. MTTFd is an extension of MTTF, and is only concerned about failures which would result in

2816-748: The first academic, general-purpose timesharing system that supported software development, CTSS , was released at MIT on an IBM 709 , later 7090 and 7094. Typewriter and Teletype devices were common control consoles for system operators through the early 1970s, although ultimately supplanted by keyboard / display devices. By the early 1970s, many mainframes acquired interactive user terminals operating as timesharing computers, supporting hundreds of users simultaneously along with batch processing. Users gained access through keyboard/typewriter terminals and later character-mode text terminal CRT displays with integral keyboards, or finally from personal computers equipped with terminal emulation software. By

2880-559: The first time. IBM received the vast majority of mainframe revenue. During the 1980s, minicomputer -based systems grew more sophisticated and were able to displace the lower end of the mainframes. These computers, sometimes called departmental computers , were typified by the Digital Equipment Corporation VAX series. In 1991, AT&T Corporation briefly owned NCR. During the same period, companies found that servers based on microcomputer designs could be deployed at

2944-466: The formula for the mdt of two components in parallel is identical to that of the mtbf for two components in series. There are many variations of MTBF, such as mean time between system aborts (MTBSA), mean time between critical failures (MTBCF) or mean time between unscheduled removal (MTBUR). Such nomenclature is used when it is desirable to differentiate among types of failures, such as critical and non-critical failures. For example, in an automobile,

3008-505: The hazard, λ {\displaystyle \lambda } , is constant. In this case, the MBTF is where λ ^ {\displaystyle {\hat {\lambda }}} is the maximum likelihood estimate of λ {\displaystyle \lambda } , maximizing the likelihood given above and k = ∑ σ i {\displaystyle k=\sum \sigma _{i}}

3072-752: The late 1950s, mainframe designs have included subsidiary hardware (called channels or peripheral processors ) which manage the I/O devices, leaving the CPU free to deal only with high-speed memory. It is common in mainframe shops to deal with massive databases and files. Gigabyte to terabyte -size record files are not unusual. Compared to a typical PC, mainframes commonly have hundreds to thousands of times as much data storage online, and can access it reasonably quickly. Other server families also offload I/O processing and emphasize throughput computing. Mainframe return on investment (ROI), like any other computing platform,

3136-677: The latest Hitachi AP10000 models are made by IBM. Unisys manufactures ClearPath Libra mainframes, based on earlier Burroughs MCP products and ClearPath Dorado mainframes based on Sperry Univac OS 1100 product lines. Hewlett Packard Enterprise sells its unique NonStop systems, which it acquired with Tandem Computers and which some analysts classify as mainframes. Groupe Bull 's GCOS , Stratus OpenVOS , Fujitsu (formerly Siemens) BS2000 , and Fujitsu- ICL VME mainframes are still available in Europe, and Fujitsu (formerly Amdahl) GS21 mainframes globally. NEC with ACOS and Hitachi with AP10000- VOS3 still maintain mainframe businesses in

3200-477: The mainframe. IBM's quarterly and annual reports in the 2000s usually reported increasing mainframe revenues and capacity shipments. However, IBM's mainframe hardware business has not been immune to the recent overall downturn in the server hardware market or to model cycle effects. For example, in the 4th quarter of 2009, IBM's System z hardware revenues decreased by 27% year over year. But MIPS (millions of instructions per second) shipments increased 4% per year over

3264-472: The mid-1990s, when CMOS mainframe designs replaced the older bipolar technology. IBM claimed that its newer mainframes reduced data center energy costs for power and cooling, and reduced physical space requirements compared to server farms . Modern mainframes can run multiple different instances of operating systems at the same time. This technique of virtual machines allows applications to run as if they were on physically distinct computers. In this role,

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3328-433: The most secure, with vulnerabilities in the low single digits, as compared to thousands for Windows , UNIX , and Linux . Software upgrades usually require setting up the operating system or portions thereof, and are non disruptive only when using virtualizing facilities such as IBM z/OS and Parallel Sysplex , or Unisys XPCL, which support workload sharing so that one system can take over another's application while it

3392-431: The new Telum microprocessor . A supercomputer is a computer at the leading edge of data processing capability, with respect to calculation speed. Supercomputers are used for scientific and engineering problems ( high-performance computing ) which crunch numbers and data, while mainframes focus on transaction processing. The differences are: Mainframes and supercomputers cannot always be clearly distinguished; up until

3456-433: The past two years. Alsop had himself photographed in 2000, symbolically eating his own words ("death to the mainframe"). In 2012, NASA powered down its last mainframe, an IBM System z9. However, IBM's successor to the z9, the z10 , led a New York Times reporter to state four years earlier that "mainframe technology—hardware, software and services—remains a large and lucrative business for I.B.M., and mainframes are still

3520-628: The primary reasons for their longevity, since they are typically used in applications where downtime would be costly or catastrophic. The term reliability, availability and serviceability (RAS) is a defining characteristic of mainframe computers. Proper planning and implementation are required to realize these features. In addition, mainframes are more secure than other computer types: the NIST vulnerabilities database, US-CERT , rates traditional mainframes such as IBM Z (previously called z Systems, System z, and zSeries), Unisys Dorado, and Unisys Libra as among

3584-408: The probability of a system failing within a certain timeframe is the inverse of its MTBF. Then, when considering series of components, failure of any component leads to the failure of the whole system, so (assuming that failure probabilities are small, which is usually the case) probability of the failure of the whole system within a given interval can be approximated as a sum of failure probabilities of

3648-408: The probability that a particular system will survive to its MTBF is 1 / e {\displaystyle 1/e} , or about 37% (i.e., it will fail earlier with probability 63%). The MTBF value can be used as a system reliability parameter or to compare different systems or designs. This value should only be understood conditionally as the “mean lifetime” (an average value), and not as

3712-406: The second after 120 hours and the third after 130 hours. The MTBF of the systems is the average of the three failure times, which is 116.667 hours. If the systems were non-repairable, then their MTTF would be 116.667 hours. In general, MTBF is the "up-time" between two failure states of a repairable system during operation as outlined here: [REDACTED] For each observation, the "down time"

3776-613: The size and throughput of databases. Batch processing, such as billing, became even more important (and larger) with the growth of e-business, and mainframes are particularly adept at large-scale batch computing. Another factor currently increasing mainframe use is the development of the Linux operating system, which arrived on IBM mainframe systems in 1999. Linux allows users to take advantage of open source software combined with mainframe hardware RAS . Rapid expansion and development in emerging markets , particularly People's Republic of China ,

3840-565: The system out of service, are not considered failures under this definition. In addition, units that are taken down for routine scheduled maintenance or inventory control are not considered within the definition of failure. The higher the MTBF, the longer a system is likely to work before failing. Mean time between failures (MTBF) describes the expected time between two failures for a repairable system. For example, three identical systems starting to function properly at time 0 are working until all of them fail. The first system fails after 100 hours,

3904-410: Was a rough consensus among industry analysts that the mainframe was a dying market as mainframe platforms were increasingly replaced by personal computer networks. InfoWorld ' s Stewart Alsop infamously predicted that the last mainframe would be unplugged in 1996; in 1993, he cited Cheryl Currid, a computer industry analyst as saying that the last mainframe "will stop working on December 31, 1999",

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3968-569: Was another Eastern Bloc manufacturer, producing the ODRA , R-32 and R-34 mainframes. Shrinking demand and tough competition started a shakeout in the market in the early 1970s—RCA sold out to UNIVAC and GE sold its business to Honeywell; between 1986 and 1990 Honeywell was bought out by Bull ; UNIVAC became a division of Sperry , which later merged with Burroughs to form Unisys Corporation in 1986. In 1984 estimated sales of desktop computers ($ 11.6 billion) exceeded mainframe computers ($ 11.4 billion) for

4032-460: Was approximately 30 kW , not accounting for the cooling systems. BESM-2 also used vacuum tubes . BESM-3M and BESM-4 were built using transistors . Their architecture was similar to that of the M-20 and M-220 series. The word size was 45 bits. Thirty BESM-4 machines were built. BESM-4 was used to create the first ever computer animation . The prototypes of both models were made in 1962–63, and

4096-456: Was capable of representing numbers in the range 10 – 10. BESM-1 had 1024 words of read–write memory using ferrite cores , and 1024 words of read-only memory based on semiconducting diodes. It also had external storage: four magnetic tape units of 30,000 words each, and fast magnetic drum storage with a capacity of 5120 words and an access rate of 800 words/second. The computer was capable of performing 8–10 K Flops . The energy consumption

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