Explain what is mainframe computer?( मेनफ्रेम कंप्यूटर क्या है समझाइए

Mainframe computer   

Also informally called a mainframe or big iron,  is a computer used primarily by large organizations for large-scale data processing for tasks such as census, industry and consumer statistics, enterprise resource planning, and large-scale transactions. Such is done for critical applications. Processing. A mainframe computer is larger 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 the 1960s, but they continue to evolve. Mainframe computers are often used as servers.                                

A single-frame IBM z15 mainframe. Larger capacity models can hold up to four frames total. This model has blue accents compared to the LinuxONE III model which has orange highlights.

 design 

  Modern mainframe designs are characterized less by raw computational speed and more by:

•  Redundant internal engineering results in higher reliability and safety
• Extensive input-output ("I/O") facilities with ability to offload to different engines
• Strict backward compatibility with older software
• Higher hardware and computational utilization rates through virtualization to support massive throughput
• Hot swapping of hardware like processor and memory

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, which is one of the primary reasons for their longevity, as they are typically used in applications where downtime would be costly or catastrophic. The terms reliability, availability, and serviceability (RAS) are a defining characteristic of mainframe computers. Realizing these features requires proper planning and implementation. Additionally, mainframes are more secure than other computer types: NIST vulnerabilities database, US-CERT, IBM Z (formerly called Z System, System Z, and ZSeries), [indistinct] traditional mainframes such as Unisys Dorado and Unisys Libra. rates. Windows as one of the most secure, with vulnerabilities in the low single digits, compared to thousands of Unix and Linux. [6] Software upgrades usually require setting up the operating system or parts of it, and are non-disruptive only when using IBM z/OS and virtualizing features such as ParallelSysPlex, or Unisys XPCL, which optimize workloads. Support sharing so that one system can take over. When someone else's application is being refreshed.

In the late 1950s, mainframes had only a rudimentary interactive interface (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 (such as airline booking) rather than for program development. However, in 1961 the first CTSS, at MIT, was released on the IBM 709, later on the 7090 and 7094. Typewriters and teletype devices were common control consoles for system operators in the early 1970s, although they were eventually replaced by keyboard/display devices.

By the early 1970s, many mainframes acquired interactive user terminals [NB1], operating as timesharing computers, supporting hundreds of users simultaneously with batch processing. Users accessed keyboard/typewriter terminals and later character-mode text [NB2] terminals via integral keyboards with CRT displays, or finally from personal computers equipped with terminal emulation software. By 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 completely eliminated classic "green screen" and color display terminal access for end users in favor of web-style user interfaces. [ citation needed ]

 features

Modern mainframes can run several different instances of an operating system at the same time. This technology of virtual machines allows applications to run as if they were physically on separate computers. In this role, a single mainframe can replace the high-functioning hardware services available to traditional servers. While mainframes pioneered this capability, virtualization is now available on most families of computer systems, although not always to the same degree or level of sophistication.

 Mainframes can add or hot swap system capacity without disrupting system function, with a degree of sophistication and granularity not typically available with most server solutions. [citation needed] Modern mainframes, notably the IBM z Server, provide two levels of virtualization: logical partitions (via the LPAR, PR/SM feature) 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 a disaster hits the first building. Testing, development, training, and production workloads for applications and databases can run on a single machine, except for extremely large demands where the capacity of a single machine may be limited. Such a two-mainframe installation can support continuous business service, avoiding both planned and unplanned interruptions. In practice, many customers use multiple mainframes linked by either parallel sysplex and shared DASD (in the case of IBM), [citation needed] or shared, geographically dispersed storage provided by EMC or Hitachi.

Mainframes are designed to handle very high volumes of input and output (I/O) and emphasize throughput computing. Since the late 1950s, [nb3] mainframe designs have included auxiliary hardware [nb4] (called channel or peripheral processors) that manage I/O devices, allowing the CPU to access only high-speed memory. becomes free to deal with. It is common in mainframe shops to deal with massive databases and files. Record files gigabyte to terabyte in size are not uncommon.Compared to a typical PC, mainframes typically have hundreds to thousands of times more data storage online,And it can be accessed quite fast. Other server families also offload I/O processing and emphasize computing throughput.

Mainframe return on investment (ROI), like any other computing platform, depends on the ability to scale, support mixed workloads, reduce labor costs, provide uninterrupted service to critical business applications, and many other risk-adjusted cost factors. resting on.

 History of mainframe computer 

 Many manufacturers and their successors produced mainframe computers from the 1950s to the early 21st century, with a gradual reduction in numbers and a gradual transition to emulation on Intel chips rather than proprietary hardware. The American group of manufacturers formerly known as "IBM and the Seven Dwarfs

Page 83  Commonly Burroughs, Univac, NCR, Control Data, Honeywell, General Electric and RCA, although some listings varied. Later, with the departure of General Electric and RCA, it became called IBM and the Bunch. IBM's dominance grew with the development of their 700/7000 series and, later, 360 series mainframes. The latter architecture has continued to evolve into its current zSeries mainframes, which, along with the then-Burroughs & Sperry (now Unisys) MCP-based and OS1100 mainframes, are among the few mainframe architectures still in existence that date back to this early period. Can find roots. While IBM's zSeries can still run 24-bit System/360 code, 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. During the Cold War the Soviet Union and Warsaw Pact countries made close copies of IBM mainframes; [citation needed] The BESM series and Strela are examples of independently designed Soviet computers. Elvro in Poland was another Eastern Bloc manufacturer, producing ODRA, R-32 and R-34 mainframes.

Declining demand and intense competition led to market turmoil in the early 1970s – RCA sold Univac and GE sold its business to Honeywell; Honeywell was purchased by Bull between 1986 and 1990; 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 those of mainframe computers ($11.4 billion) for the first time. IBM received the vast majority of mainframe revenues. [21] During the 1980s, minicomputer-based systems became more sophisticated and capable of displacing the lower end of 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 a fraction of the acquisition price and provided local users with much more control over their systems, given the IT policies and practices of the time. The terminals used to interact with mainframe systems were gradually replaced by personal computers. As a result, demand declined and new mainframe installations remained confined primarily to financial services and government. In the early 1990s, there was a consensus among industry analysts that mainframes were a dying market as mainframe platforms were rapidly being replaced by personal computer networks. InfoWorld's Stewart Alsop infamously predicted that the last mainframe would be unplugged in 1996; In 1993, he quoted computer industry analyst Cheryl Currid as saying that the last mainframe "will stop working on December 31, 1999",A reference to the anticipated Year 2000 problem (Y2K).

This trend began to change in the late 1990s as corporations found new uses for their existing mainframes and as the price of data networking fell in much of the world, leading to a trend 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 the size and throughput of databases. Batch processing such as billing has become even more important (and larger) with the growth of e-business, and mainframes are particularly adept at large-scale batch computing. Another factor currently driving 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 growth in emerging markets, particularly the People's Republic of China, is also fueling major mainframe investments to solve exceptionally difficult computing problems, for example in many industries (banking, insurance) 1 Providing a unified, extremely high volume online transaction processing database for billions of consumers. credit reporting, government services, etc.) In the late 2000s, IBM introduced the 64-bit z/ architecture, acquired several software companies such as Cognos, and introduced those software products into mainframes. IBM's quarterly and annual reports in the 2000s generally reported growth in mainframe revenues and capacity shipments. However, IBM's mainframe hardware business has not been immune from the recent overall slowdown in the server hardware market or model cycle effects. For example, in the fourth quarter of 2009, IBM's System z hardware revenue decreased by 27% year over year. But MIPS (millions of instructions per second) shipments have increased by 4 per year over the past two years. [23] Alsop was photographed in 2000 symbolically eating his own words ("Death of the mainframe").

Alsop was photographed in 2000 symbolically eating his own words ("Death of the mainframe").