mainframe computer this article contains content that is written like an advertisement please help improve it by removing promotional content and inappropriate external links and by adding encyclopedic content written from a neutral point of view september 2018 learn how and when to remove this template message for other uses see mainframe disambiguation a pair of ibm mainframes on the left is the ibm z systems z13 on the right is the ibm linuxone rockhopper an ibm system z9 mainframe mainframe computers colloquially referred to as big iron are computers used primarily by large organizations for critical applications bulk data processing such as census industry and consumer statistics enterprise resource planning and transaction processing they are larger and have more processing power than some other classes of computers minicomputers servers workstations and personal computers the term originally referred to the large cabinets called main frames that housed the central processing unit and main memory of early computers most largescale computer system architectures were established in the 1960s but continue to evolve mainframe computers are often used as servers design modern mainframe design is characterized less by raw singletask computational speed typically defined as mips millions of instructions per second rate or flops floatingpoint operations per second and more by redundant internal engineering resulting in high reliability and security extensive inputoutput io facilities with the ability to offload to separate engines strict backward compatibility with older software high hardware and computational utilization rates through virtualization to support massive throughput their high stability and reliability enable these machines to run uninterrupted for decades mainframes have high availability one of 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 is required to realize these features in addition mainframes are more secure than other computer types the nist vulnerabilities database uscert rates traditional mainframes such as ibm z previously called z systems system z and zseries unisys dorado and unisys libra as among the most secure with vulnerabilities in the low single digits as compared with thousands for windows unix and linux software upgrades usually require setting up the operating system or portions thereof and are nondisruptive only when using virtualizing facilities such as ibm zos and parallel sysplex or unisys xpcl which support workload sharing so that one system can take over anothers application while it 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 tapebased 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 eg airline booking rather than program development typewriter and teletype devices were common control consoles for system operators through the early 1970s although ultimately supplanted by keyboarddisplay devices by the early 1970s many mainframes acquired interactive user terminals the infrastructure requirements were drastically reduced during the mid1990s 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 characteristics inside an ibm system z9 mainframe 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 a single mainframe can replace higherfunctioning 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 a level of sophistication not usually available with most server solutions or with shared geographically dispersed storage provided by emc or hitachi mainframes are designed to handle very high volume input and output io and emphasize throughput computing since the late1950s and can access it reasonably quickly other server families also offload io processing and emphasize throughput computing mainframe return on investment roi like any other computing platform is dependent on its ability to scale support mixed workloads reduce labor costs deliver uninterrupted service for critical business applications and several other riskadjusted cost factors mainframes also have execution integrity characteristics for fault tolerant computing for example z900 z990 system z9 and system z10 servers effectively execute resultoriented 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 hardwarelevel feature also found in hps nonstop systems is known as lockstepping because both processors take their steps ie instructions together not all applications absolutely need the assured integrity that these systems provide but many do such as financial transaction processing current market ibm with z systems continues to be a major manufacturer in the mainframe market unisys manufactures clearpath libra mainframes based on earlier burroughs mcp products and clearpath dorado mainframes based on sperry univac os 1100 product lines in 2000 hitachi codeveloped the zseries z900 with ibm to share expenses but subsequently the two companies have not collaborated on new hitachi models hewlettpackard sells its unique nonstop systems which it acquired with tandem computers and which some analysts classify as mainframes groupe bulls gcos fujitsu formerly siemens bs2000 and fujitsuicl vme mainframes are still available in europe and fujitsu formerly amdahl gs21 mainframes globally nec with acos and hitachi with ap10000vos3 still maintain mainframe hardware businesses in the japanese market the amount of vendor investment in mainframe development varies with market share fujitsu and hitachi both continue to use custom s390compatible processors as well as other cpus including power and xeon for lowerend systems bull uses a mixture of itanium and xeon processors nec uses xeon processors for its lowend acos2 line but develops the custom noah6 processor for its highend acos4 series ibm continues to pursue a different business strategy of mainframe investment and growth furthermore there exists a market for software applications to manage the performance of mainframe implementations in addition to ibm significant players in this market include bmc history this section needs additional citations for verification please help improve this article by adding citations to reliable sources unsourced material may be challenged and removed july 2008 learn how and when to remove this template message an ibm 704 mainframe 1964 several manufacturers produced mainframe computers from the late 1950s through the 1970s the us group of manufacturers was first known as ibm and the seven dwarfsp83 usually burroughs univac ncr control data honeywell general electric and rca although some lists varied later with the departure of general electric and rca it was referred to as ibm and the bunch ibms dominance grew out of their 7007000 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 mcpbased and os1100 mainframes are among the few mainframe architectures still extant that can trace their roots to this early period while ibms zseries can still run 24bit system360 code the 64bit zseries and system z9 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 an independently designed soviet computer shrinking demand and tough competition started a shakeout in the market in the early 1970srca sold out to univac and ge sold its business to honeywell in the 1980s honeywell was bought out by bull univac became a division of sperry which later merged with burroughs to form unisys corporation in 1986 during the 1980s minicomputerbased systems grew more sophisticated and were able to displace the lowerend of the mainframes these computers sometimes called departmental computers were typified by the dec vax in 1991 att corporation briefly owned ncr during the same period companies found that servers based on microcomputer designs could be deployed at 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 was a rough consensus among industry analysts that the mainframe was a dying market as mainframe platforms were increasingly replaced by personal computer networks infoworlds 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 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 ebusiness also dramatically increased the number of backend transactions processed by mainframe software as well as the size and throughput of databases batch processing such as billing became even more important and larger with the growth of ebusiness and mainframes are particularly adept at largescale batch computing another factor currently increasing mainframe use is the development of the linux operating system which arrived on ibm mainframe systems in 1999 and is typically run in scores or up to 8000 virtual machines on a single mainframe linux allows users to take advantage of open source software combined with mainframe hardware ras rapid expansion and development in emerging markets particularly peoples republic of china is also spurring major mainframe investments to solve exceptionally difficult computing problems eg 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 64bit zarchitecture acquired numerous software companies such as cognos and introduced those software products to the mainframe ibms quarterly and annual reports in the 2000s usually reported increasing mainframe revenues and capacity shipments however ibms 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 ibms system z hardware revenues decreased by 27 year over year but mips millions of instructions per second shipments increased 4 per year over the past two years in 2012 nasa powered down its last mainframe an ibm system z9 in 2015 ibm launched the ibm z13 differences from supercomputers 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 highperformance computing which crunch numbers and data while mainframes focus on transaction processing the differences are mainframes are built to be reliable for transaction processing measured by tpcmetrics not used or helpful for most supercomputing applications as it is commonly understood in the business world the commercial exchange of goods services or money updates a database system for inventory control goods airline reservations services or banking money by adding a record a transaction may refer to a set of operations including disk readwrites operating system calls or some form of data transfer from one subsystem to another which is not measured by the processing speed of the cpu transaction processing is not exclusive to mainframes but is also used by microprocessorbased servers and online networks supercomputer performance is measured in floating point operations per second flops in 2007 an amalgamation of the different technologies and architectures for supercomputers and mainframes has led to the socalled gameframe computer types failover gameframe channel io cloud computing notes ibm systems mainframe magazine wikimedia commons has media related to mainframe computers ibm z systems mainframes mainframe computer support forum since 1998 univac 9400 a mainframe from the 1960s still in use in a german computer museum lectures in the history of computing mainframes archived copy from the internet archive vtecomputer sizesclasses of computersmicrocomputerpersonalcomputerstationary workstation desktop home personal supercomputer portable tabletop smart tv interactive kiosk game arcade cabinet system board home console microconsole sff nettop plug smart speaker mobilelaptop desktop replacement 2in1 subnotebook netbook smartbook ultrabook ultramobile pc tablet ultramobile pc 2in1 phablet tabletop handheld handheld pc palmtop pc pocket computer pda electronic organizer mobile phone feature phone smartphone phablet pmp ereader handheld game console portablemobile data terminal calculator scientific programmable graphing wearable digital wristwatch calculator watch smartwatch smartglasses smart ring midrange server minicomputer supermini large super mainframe minisuper others microcontroller nanocomputer singleboard computer smartdust wireless sensor network 