![IBM System Z9 (type 2094 front)](https://upload.wikimedia.org/wikipedia/commons/6/62/IBM_System_Z9_%28type_2094_front%29.jpg)
A mainframe computer, informally called a mainframe or big iron, is a
computer
A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as C ...
used primarily by large organizations for critical applications like bulk
data processing
Data processing is the collection and manipulation of digital data to produce meaningful information.
Data processing is a form of ''information processing'', which is the modification (processing) of information in any manner detectable by an ...
for tasks such as
census
A census is the procedure of systematically acquiring, recording and calculating information about the members of a given population. This term is used mostly in connection with national population and housing censuses; other common censuses incl ...
es, industry and consumer
statistics
Statistics (from German language, German: ''wikt:Statistik#German, Statistik'', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of ...
,
enterprise resource planning
Enterprise resource planning (ERP) is the integrated management of main business processes, often in real time and mediated by software and technology. ERP is usually referred to as a category of Business management tools, business management ...
, and large-scale
transaction processing
Transaction processing is information processing in computer science that is divided into individual, indivisible operations called ''transactions''. Each transaction must succeed or fail as a complete unit; it can never be only partially comple ...
. A mainframe computer is large but not as large as a
supercomputer
A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructions ...
and has more processing power than some other classes of computers, such as
minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
s,
server
Server may refer to:
Computing
*Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients
Role
* Waiting staff, those who work at a restaurant or a bar attending customers and su ...
s,
workstation
A workstation is a special computer designed for technical or scientific applications. Intended primarily to be used by a single user, they are commonly connected to a local area network and run multi-user operating systems. The term ''workstat ...
s, and
personal computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s. Most large-scale computer-system architectures were established in 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
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...
and main
memory
Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...
of early computers. Later, the term ''mainframe'' was used to distinguish high-end commercial computers from less powerful machines.
Design
Modern mainframe design is characterized less by raw computational speed and more by:
* Redundant internal engineering resulting in high reliability and security
* Extensive input-output ("I/O") facilities with the ability to offload to separate engines
* Strict
backward compatibility
Backward compatibility (sometimes known as backwards compatibility) is a property of an operating system, product, or technology that allows for interoperability with an older legacy system, or with input designed for such a system, especially i ...
with older software
* High hardware and computational utilization rates through virtualization to support massive
throughput
Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel, such as Ethernet or packet radio, in a communication network. The data that these messages contain may be delivered ov ...
.
*
Hot-swapping of hardware, such as processors and memory.
Their high stability and reliability enable these machines to run uninterrupted for very long periods of time, with
mean time between failures
Mean time between failures (MTBF) is the predicted elapsed time between inherent failures of a mechanical or electronic system during normal system operation. MTBF can be calculated as the arithmetic mean (average) time between failures of a system ...
(MTBF) measured in decades.
Mainframes have
high availability
High availability (HA) is a characteristic of a system which aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period.
Modernization has resulted in an increased reliance on these systems. Fo ...
, 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
Reliability, availability and serviceability (RAS), also known as reliability, availability, and maintainability (RAM), is a computer hardware engineering term involving reliability engineering, high availability, and serviceability design. The p ...
(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
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
vulnerabilities database,
US-CERT
The United States Computer Emergency Readiness Team (US-CERT) is an organization within the Department of Homeland Security’s (DHS) Cybersecurity and Infrastructure Security Agency (CISA). Specifically, US-CERT is a branch of the Office of C ...
, 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
Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...
,
UNIX
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...
, and
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...
. Software upgrades usually require setting up the
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
or portions thereof, and are non-disruptive only when using
virtualizing
In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something at the same abstraction level, including virtual computer hardware platforms, stor ...
facilities such as IBM
z/OS
z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest:
* O ...
and
Parallel Sysplex
In computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems ...
, or Unisys XPCL, which support workload sharing so that one system can take over another's 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
A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to d ...
,
paper tape
Five- and eight-hole punched paper tape
Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop
Punched tape or perforated paper tape is a form of data storage ...
, or
magnetic tape
Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magne ...
to transfer data and programs. They operated in
batch
Batch may refer to:
Food and drink
* Batch (alcohol), an alcoholic fruit beverage
* Batch loaf, a type of bread popular in Ireland
* A dialect term for a bread roll used in North Warwickshire, Nuneaton and Coventry, as well as on the Wirral ...
mode to support
back office
A back office in most corporations is where work that supports ''front office'' work is done. The front office is the "face" of the company and is all the resources of the company that are used to make sales and interact with customers and client ...
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
Continuous stationery (UK) or continuous form paper (US) is paper which is designed for use with dot-matrix and line printers with appropriate paper-feed mechanisms. Other names include ''fan-fold paper'', ''sprocket-feed paper'', ''burst paper' ...
. When interactive user terminals were introduced, they were used almost exclusively for applications (e.g.
airline booking) rather than program development. However, in 1961 the first academic, general-purpose timesharing system that supported software development,
CTSS, was released at
MIT
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the mo ...
on an
IBM 709
The IBM 709 was a computer system, initially announced by IBM in January 1957 and first installed during August 1958. The 709 was an improved version of its predecessor, the IBM 704, and was the third of the IBM 700/7000 series of scientific com ...
, later 7090 and 7094.
Typewriter
A typewriter is a mechanical or electromechanical machine for typing characters. Typically, a typewriter has an array of keys, and each one causes a different single character to be produced on paper by striking an inked ribbon selectivel ...
and
Teletype
A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Initia ...
devices were common control consoles for system operators through the early 1970s, although ultimately supplanted by
keyboard
Keyboard may refer to:
Text input
* Keyboard, part of a typewriter
* Computer keyboard
** Keyboard layout, the software control of computer keyboards and their mapping
** Keyboard technology, computer keyboard hardware and firmware
Music
* Musi ...
/
display
Display may refer to:
Technology
* Display device, output device for presenting information, including:
** Cathode ray tube, video display that provides a quality picture, but can be very heavy and deep
** Electronic visual display, output devi ...
devices.
By the early 1970s, many mainframes acquired interactive user terminals
[Some had been introduced in the 1960s, but their deployment became more common in the 1970s] operating as
timesharing
In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1
Its emergence a ...
computers, supporting hundreds of users simultaneously along with batch processing. Users gained access through keyboard/typewriter terminals and specialized text
[Graphics terminals were available but less common.] terminal
Terminal may refer to:
Computing Hardware
* Terminal (electronics), a device for joining electrical circuits together
* Terminal (telecommunication), a device communicating over a line
* Computer terminal, a set of primary input and output devic ...
CRT
CRT or Crt may refer to:
Science, technology, and mathematics Medicine and biology
* Calreticulin, a protein
*Capillary refill time, for blood to refill capillaries
*Cardiac resynchronization therapy and CRT defibrillator (CRT-D)
* Catheter-re ...
displays with integral keyboards, or later from
personal computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s equipped with
terminal emulation
A terminal emulator, or terminal application, is a computer program that emulates a video terminal within some other display architecture. Though typically synonymous with a shell or text terminal, the term ''terminal'' covers all remote termin ...
software. By the 1980s, many mainframes supported 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
GUI
The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...
s. After 2000, modern mainframes partially or entirely phased out classic "
green screen
Chroma key compositing, or chroma keying, is a visual-effects and post-production technique for compositing (layering) two images or video streams together based on colour hues ( chroma range). The technique has been used in many fields to r ...
" and color display terminal access for end-users in favour of Web-style user interfaces.
The infrastructure requirements were drastically reduced during the mid-1990s, when
CMOS
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFE ...
mainframe designs replaced the older
bipolar
Bipolar may refer to:
Astronomy
* Bipolar nebula, a distinctive nebular formation
* Bipolar outflow, two continuous flows of gas from the poles of a star
Mathematics
* Bipolar coordinates, a two-dimensional orthogonal coordinate system
* 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
A server farm or server cluster is a collection of computer servers, usually maintained by an organization to supply server functionality far beyond the capability of a single machine. They often consist of thousands of computers which require ...
.
Characteristics
![IBM System Z9 (type 2094 inside)](https://upload.wikimedia.org/wikipedia/commons/6/61/IBM_System_Z9_%28type_2094_inside%29.jpg)
Modern mainframes can run multiple different instances of operating systems at the same time. This technique of
virtual machine
In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardw ...
s allows applications to run as if they were on physically distinct computers. In this role, 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
Hot swapping is the replacement or addition of components to a computer system without stopping, shutting down, or rebooting the system; hot plugging describes the addition of components only. Components which have such functionality are said ...
system capacity without disrupting system function, with specificity and granularity to a level of sophistication not usually available with most server solutions. Modern mainframes, notably the IBM
zSeries
IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers.
In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest mo ...
,
System z9
IBM System z9 is a line of IBM mainframe computers. The first models were available on September 16, 2005. The System z9 also marks the end of the previously used eServer zSeries naming convention. It was also the last mainframe computer ...
and
System z10
A system is a group of interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment, is described by its boundaries, structure and purpose and expressed ...
servers, offer two levels of
virtualization
In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something at the same abstraction level, including virtual computer hardware platforms, stor ...
: logical partitions (
LPAR
A logical partition (LPAR) is a subset of a computer's hardware resources, virtualized as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions, each hosting a separate instance of an operating ...
s, via the
PR/SM
A logical partition (LPAR) is a subset of a computer's hardware resources, virtualized as a separate computer. In effect, a physical machine can be partitioned into multiple logical partitions, each hosting a separate instance of an operating ...
facility) and virtual machines (via the
z/VM
z/VM is the current version in IBM's VM family of virtual machine operating systems. z/VM was first released in October 2000 and remains in active use and development . It is directly based on technology and concepts dating back to the 1960s, wi ...
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 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
In computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems ...
and shared
DASD
A direct-access storage device (DASD) (pronounced ) is a secondary storage device in which "each physical record has a discrete location and a unique address". The term was coined by IBM to describe devices that allowed random access to data, t ...
(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 the late 1950s,
[E.g., the ]IBM 709
The IBM 709 was a computer system, initially announced by IBM in January 1957 and first installed during August 1958. The 709 was an improved version of its predecessor, the IBM 704, and was the third of the IBM 700/7000 series of scientific com ...
had channels in 1958 mainframe designs have included subsidiary hardware
[sometimes computers, sometimes more limited] (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
database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases sp ...
s and files.
Gigabyte
The gigabyte () is a multiple of the unit byte for digital information. The prefix ''giga'' means 109 in the International System of Units (SI). Therefore, one gigabyte is one billion bytes. The unit symbol for the gigabyte is GB.
This defini ...
to
terabyte
The byte is a units of information, unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character (computing), character of text in a computer and for this ...
-size record files are not unusual. Compared to a typical PC, mainframes commonly have hundreds to thousands of times as much
data storage
Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are conside ...
online, and can access it reasonably quickly. Other server families also offload I/O processing and emphasize throughput computing.
Mainframe
return on investment
Return on investment (ROI) or return on costs (ROC) is a ratio between net income (over a period) and investment (costs resulting from an investment of some resources at a point in time). A high ROI means the investment's gains compare favourably ...
(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 risk-adjusted cost factors.
Mainframes also have execution integrity characteristics for
fault tolerant
Fault tolerance is the property that enables a system to continue operating properly in the event of the failure of one or more faults within some of its components. If its operating quality decreases at all, the decrease is proportional to the ...
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, 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.
Current market
IBM, with
z Systems, continues to be a major manufacturer in the mainframe market. In 2000,
Hitachi
() is a Japanese multinational corporation, multinational Conglomerate (company), conglomerate corporation headquartered in Chiyoda, Tokyo, Japan. It is the parent company of the Hitachi Group (''Hitachi Gurūpu'') and had formed part of the Ni ...
co-developed the
zSeries
IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers.
In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest mo ...
z900 with IBM to share expenses, and the latest Hitachi AP10000 models are made by IBM.
Unisys
Unisys Corporation is an American multinational information technology (IT) services and consulting company headquartered in Blue Bell, Pennsylvania. It provides digital workplace solutions, cloud, applications, and infrastructure solutions, e ...
manufactures
ClearPath Libra mainframes, based on earlier
Burroughs MCP
The MCP (Master Control Program) is the operating system of the Burroughs small, medium and large systems, including the Unisys Clearpath/MCP systems.
MCP was originally written in 1961 in ESPOL (Executive Systems Problem Oriented Language). In ...
products and ClearPath Dorado mainframes based on
Sperry Univac
UNIVAC (Universal Automatic Computer) was a line of electronic digital stored-program computers starting with the products of the Eckert–Mauchly Computer Corporation. Later the name was applied to a division of the Remington Rand company and ...
OS 1100 product lines.
Hewlett-Packard
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components ...
sells its unique
NonStop systems, which it acquired with
Tandem Computers
Tandem Computers, Inc. was the dominant manufacturer of fault-tolerant computer systems for Automated teller machine, ATM networks, banks, stock exchanges, telephone switching centers, and other similar commercial transaction processing applicati ...
and which some analysts classify as mainframes.
Groupe Bull
Bull SAS (also known as Groupe Bull, Bull Information Systems, or simply Bull) is a French computer company headquartered in Les Clayes-sous-Bois, in the western suburbs of Paris. The company has also been known at various times as Bull General El ...
's
GCOS,
Stratus
Stratus may refer to:
Weather
*Stratus cloud, a cloud type
**Nimbostratus cloud, a cloud type
**Stratocumulus cloud, a cloud type
**Altostratus cloud, a cloud type
**Altostratus undulatus cloud, a cloud type
**Cirrostratus cloud, a cloud type
Mus ...
OpenVOS
Stratus VOS (Virtual Operating System) is a proprietary operating system running on Stratus Technologies fault-tolerant computer systems. VOS is available on Stratus's ftServer and Continuum platforms. VOS customers use it to support high-volume ...
,
Fujitsu
is a Japanese multinational information and communications technology equipment and services corporation, established in 1935 and headquartered in Tokyo. Fujitsu is the world's sixth-largest IT services provider by annual revenue, and the la ...
(formerly Siemens)
BS2000
BS2000 is an operating system for IBM 390-compatible mainframe computers developed in the 1970s by Siemens (Data Processing Department EDV) and from early 2000s onward by Fujitsu Technology Solutions.
Unlike other mainframe systems, BS2000 pr ...
, and Fujitsu-
ICL VME
VME (''Virtual Machine Environment'') is a Mainframe computer, mainframe operating system developed by the UK company International Computers Limited (ICL, now part of the Fujitsu group). Originally developed in the 1970s (as VME/B, later VME 290 ...
mainframes are still available in Europe, and Fujitsu (formerly Amdahl)
GS21 mainframes globally.
NEC
is a Japanese multinational corporation, multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It prov ...
with
ACOS ACOS or Acos may refer to:
* Arccosine, an inverse trigonometric function
* The Advanced Comprehensive Operating System mainframe computer operating system
* Acos District in Peru
* Acos Vinchos District in Peru
* A Crown of Swords novel
See a ...
and Hitachi with AP10000-
VOS3 still maintain mainframe 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 S/390-compatible processors, as well as other CPUs (including POWER and Xeon) for lower-end systems. Bull uses a mixture of
Itanium
Itanium ( ) is a discontinued family of 64-bit Intel microprocessors that implement the Intel Itanium architecture (formerly called IA-64). Launched in June 2001, Intel marketed the processors for enterprise servers and high-performance computin ...
and
Xeon
Xeon ( ) is a brand of x86 microprocessors designed, manufactured, and marketed by Intel, targeted at the non-consumer workstation, server, and embedded system markets. It was introduced in June 1998. Xeon processors are based on the same arc ...
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 the
zEC12. Unisys produces code compatible mainframe systems that range from laptops to cabinet-sized mainframes that use homegrown CPUs as well as
Xeon
Xeon ( ) is a brand of x86 microprocessors designed, manufactured, and marketed by Intel, targeted at the non-consumer workstation, server, and embedded system markets. It was introduced in June 1998. Xeon processors are based on the same arc ...
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, Maintec Technologies,
Compuware
Compuware Corporation was an American software company based in Detroit, Michigan. The company offers products aimed at the information technology (IT) departments of large businesses, and its services also include testing, development, automation ...
, and
CA Technologies
CA Technologies, formerly known as CA, Inc. and Computer Associates International, Inc., is an American multinational corporation headquartered in New York City. It is primarily known for its business-to-business (B2B) software with a product po ...
. Starting in the 2010s,
cloud computing
Cloud computing is the on-demand availability of computer system resources, especially data storage ( cloud storage) and computing power, without direct active management by the user. Large clouds often have functions distributed over mul ...
is now a less expensive, more scalable alternative commonly called
Big Data
Though used sometimes loosely partly because of a lack of formal definition, the interpretation that seems to best describe Big data is the one associated with large body of information that we could not comprehend when used only in smaller am ...
.
History
![IBM 701console](https://upload.wikimedia.org/wikipedia/commons/a/af/IBM_701console.jpg)
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
UNIVAC (Universal Automatic Computer) was a line of electronic digital stored-program computers starting with the products of the Eckert–Mauchly Computer Corporation. Later the name was applied to a division of the Remington Rand company an ...
,
NCR,
Control Data
Control Data Corporation (CDC) was a mainframe and supercomputer firm. CDC was one of the nine major United States computer companies through most of the 1960s; the others were IBM, Burroughs Corporation, DEC, NCR, General Electric, Honeywel ...
,
Honeywell
Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building technologies, performance ma ...
,
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energ ...
and
RCA
The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
, although some lists varied. Later, with the departure of General Electric and RCA, it was referred to as IBM and the
BUNCH
Bunch may refer to:
* Bunch (surname)
* Bunch Davis (), American baseball player in the Negro leagues
* BUNCH, nickname of five computer manufacturing companies, IBM's main competitors in the 1970s
* Tussock (grass) or bunch grass, members of the ...
. IBM's dominance grew out of their
700/7000 series and, later, the development of the
360 360 may refer to:
* 360 (number)
* 360 AD, a year
* 360 BC, a year
* 360 degrees, a circle
Businesses and organizations
* 360 Architecture, an American architectural design firm
* Ngong Ping 360, a tourism project in Lantau Island, Hong Kong
* Q ...
series mainframes. The latter architecture has continued to evolve into their current zSeries mainframes which, along with the then Burroughs and Sperry (now
Unisys
Unisys Corporation is an American multinational information technology (IT) services and consulting company headquartered in Blue Bell, Pennsylvania. It provides digital workplace solutions, cloud, applications, and infrastructure solutions, e ...
)
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, the 64-bit zSeries and System z9 CMOS servers have nothing physically in common with the older systems. Notable manufacturers outside the US were
Siemens
Siemens AG ( ) is a German multinational conglomerate corporation and the largest industrial manufacturing company in Europe headquartered in Munich with branch offices abroad.
The principal divisions of the corporation are ''Industry'', '' ...
and
Telefunken
Telefunken was a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the ''Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ('General electricity company').
The name "Telefunken" app ...
in
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
,
ICL in the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
,
Olivetti
Olivetti S.p.A. is an Italian manufacturer of computers, tablets, smartphones, printers and other such business products as calculators and fax machines. Headquartered in Ivrea, in the Metropolitan City of Turin, the company has been part of ...
in Italy, and
Fujitsu
is a Japanese multinational information and communications technology equipment and services corporation, established in 1935 and headquartered in Tokyo. Fujitsu is the world's sixth-largest IT services provider by annual revenue, and the la ...
,
Hitachi
() is a Japanese multinational corporation, multinational Conglomerate (company), conglomerate corporation headquartered in Chiyoda, Tokyo, Japan. It is the parent company of the Hitachi Group (''Hitachi Gurūpu'') and had formed part of the Ni ...
,
Oki
Oki or Ōki may refer to:
Places
*Oki District, Shimane, a district in Shimane Prefecture, Japan
*Oki Islands, an archipelago in the Sea of Japan
*Oki Province, a former province of Japan
*Ōki, Fukuoka, a town in southern Japan
*Oki Airport, the ...
, and
NEC
is a Japanese multinational corporation, multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It prov ...
in
Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
. The
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
and
Warsaw Pact
The Warsaw Pact (WP) or Treaty of Warsaw, formally the Treaty of Friendship, Cooperation and Mutual Assistance, was a collective defense treaty signed in Warsaw, Poland, between the Soviet Union and seven other Eastern Bloc socialist republic ...
countries manufactured close copies of IBM mainframes during the
Cold War
The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
; the
BESM
BESM (БЭСМ) is the name of a series of Soviet mainframe computers built in 1950–60s. The name is an acronym for "Bolshaya Elektronno-Schetnaya Mashina" ("Большая Электронно-Счётная Машина"), literally "Large E ...
series and
Strela are examples of an independently designed Soviet computer.
Shrinking demand and tough competition started a
shakeout
Shakeout is a term used in business and economics to describe the consolidation of an industry or sector, in which businesses are eliminated or acquired through competition. It may also refer to a situation in which many investors exit their pos ...
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
A bull is an intact (i.e., not castrated) adult male of the species ''Bos taurus'' (cattle). More muscular and aggressive than the females of the same species (i.e., cows), bulls have long been an important symbol in many religions,
includin ...
; UNIVAC became a division of
Sperry Sperry may refer to:
Places
In the United States:
*Sperry, Iowa, community in Des Moines County
*Sperry, Missouri
*Sperry, Oklahoma, town in Tulsa County
*Sperry Chalet, historic backcountry chalet, Glacier National Park, Montana
*Sperry Glacier, ...
, which later merged with Burroughs to form
Unisys
Unisys Corporation is an American multinational information technology (IT) services and consulting company headquartered in Blue Bell, Pennsylvania. It provides digital workplace solutions, cloud, applications, and infrastructure solutions, e ...
Corporation in 1986.
In 1984 estimated sales of desktop computers ($11.6 billion) exceeded mainframe computers ($11.4 billion) for the first time. IBM received the vast majority of mainframe revenue.
During the 1980s,
minicomputer
A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...
-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
Digital Equipment Corporation (DEC ), using the trademark Digital, was a major American company in the computer industry from the 1960s to the 1990s. The company was co-founded by Ken Olsen and Harlan Anderson in 1957. Olsen was president unt ...
VAX
VAX (an acronym for Virtual Address eXtension) is a series of computers featuring a 32-bit instruction set architecture (ISA) and virtual memory that was developed and sold by Digital Equipment Corporation (DEC) in the late 20th century. The VA ...
series.
In 1991,
AT&T Corporation
AT&T Corporation, originally the American Telephone and Telegraph Company, is the subsidiary of AT&T Inc. that provides voice, video, data, and Internet telecommunications and professional services to businesses, consumers, and government agen ...
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 computer
A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...
s. 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.
InfoWorld
''InfoWorld'' (abbreviated IW) is an information technology media business. Founded in 1978, it began as a monthly magazine. In 2007, it transitioned to a web-only publication. Its parent company today is International Data Group, and its siste ...
's
Stewart Alsop
Stewart Johonnot Oliver Alsop (May 17, 1914 – May 26, 1974) was an American newspaper columnist and political analyst.
Early life
Alsop was born and raised in Avon, Connecticut, from an old Yankee family. Alsop attended Groton School and Yale ...
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
The year 2000 problem, also known as the Y2K problem, Y2K scare, millennium bug, Y2K bug, Y2K glitch, Y2K error, or simply Y2K refers to potential computer errors related to the Time formatting and storage bugs, formatting and storage of cale ...
(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
Electronic business (or "Online Business" or "e-business") is any kind of business or commercial transaction that includes sharing information across the internet. Commerce constitutes the exchange of products and services between businesses, grou ...
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, 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
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...
operating system, which
arrived on IBM mainframe systems in 1999 and is typically run in scores or up to c. 8,000 virtual machines on a single mainframe. Linux allows users to take advantage of
open source software
Open-source software (OSS) is computer software that is released under a license in which the copyright holder grants users the rights to use, study, change, and distribute the software and its source code to anyone and for any purpose. Open ...
combined with mainframe hardware
RAS
Ras or RAS may refer to:
Arts and media
* RAS Records Real Authentic Sound, a reggae record label
* Rundfunk Anstalt Südtirol, a south Tyrolese public broadcasting service
* Rás 1, an Icelandic radio station
* Rás 2, an Icelandic radio stati ...
. Rapid expansion and development in
emerging markets
An emerging market (or an emerging country or an emerging economy) is a market that has some characteristics of a developed market, but does not fully meet its standards. This includes markets that may become developed markets in the future or were ...
, particularly
People's Republic of China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, 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
z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architecture-b ...
, acquired numerous software companies such as
Cognos
Cognos Incorporated was an Ottawa, Ontario-based company making business intelligence (BI) and performance management (PM) software. Founded in 1969, at its peak Cognos employed almost 3,500 people and served more than 23,000 customers in over 1 ...
and introduced those software products to 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
IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers.
In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest mode ...
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. Alsop had himself photographed in 2000, symbolically eating his own words ("death of the mainframe").
In 2012,
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
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 the back-office engines behind the world's financial markets and much of global commerce". , while mainframe technology represented less than 3% of IBM's revenues, it "continue
to play an outsized role in Big Blue's results".
In 2015, IBM launched the
IBM z13, in June 2017 the IBM
z14, in September 2019 the IBM
z15 and on April 5th 2022 they announced IBM's latest mainframe system, the
IBM z16, featuring among other things an "integrated on-chip AI accelerator" and the new
Telum microprocessor.
Differences from supercomputers
A
supercomputer
A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructions ...
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
High-performance computing (HPC) uses supercomputers and computer clusters to solve advanced computation problems.
Overview
HPC integrates systems administration (including network and security knowledge) and parallel programming into a mult ...
) which crunch numbers and data, while mainframes focus on transaction processing. The differences are:
* Mainframes are built to be reliable for
transaction processing
Transaction processing is information processing in computer science that is divided into individual, indivisible operations called ''transactions''. Each transaction must succeed or fail as a complete unit; it can never be only partially comple ...
(measured by
TPC-metrics; 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. A typical transaction, as defined by the
Transaction Processing Performance Council In online transaction processing (OLTP), information systems typically facilitate and manage transaction-oriented applications. This is contrasted with online analytical processing.
The term "transaction" can have two different meanings, both of wh ...
, 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 read/writes, 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
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...
. Transaction processing is not exclusive to mainframes but is also used by microprocessor-based servers and online networks.
* Supercomputer performance is measured in
floating point
In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can be ...
operations per second (
FLOPS
In computing, floating point operations per second (FLOPS, flops or flop/s) is a measure of computer performance, useful in fields of scientific computations that require floating-point calculations. For such cases, it is a more accurate meas ...
) or in
traversed edges per second The number of traversed edges per second (TEPS) that can be performed by a supercomputer cluster is a measure of both the communications capabilities and computational power of the machine. This is in contrast to the more standard metric of floating ...
or TEPS, metrics that are not very meaningful for mainframe applications, while mainframes are sometimes measured in millions of instructions per second (
MIPS), although the definition depends on the instruction mix measured. Examples of integer operations measured by MIPS include adding numbers together, checking values or moving data around in memory (while moving information to and from storage, so-called
I/O is most helpful for mainframes; and within memory, only helping indirectly). Floating point operations are mostly addition, subtraction, and multiplication (of
''binary'' floating point in supercomputers; measured by FLOPS) with enough digits of precision to model continuous phenomena such as weather prediction and nuclear simulations (only recently standardized
''decimal'' floating point, not used in supercomputers, are appropriate for
monetary
Money is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular country or socio-economic context. The primary functions which distinguish money are as ...
values such as those useful for mainframe applications). In terms of computational speed, supercomputers are more powerful.
Mainframes and supercomputers cannot always be clearly distinguished; up until 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
The HITAC S-3000 is a former family of vector supercomputers, which was developed, manufactured and marketed by Hitachi. Announced in April 1992, the family succeeded the HITAC S-820. The S-3000 family comprised the low-end and mid-range S-3600 ...
, which was instruction-set compatible with
IBM System/370
The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path f ...
mainframes, and could run the
Hitachi VOS3
Multiple Virtual Storage, more commonly called MVS, was the most commonly used operating system on the System/370 and System/390 IBM mainframe computers. IBM developed MVS, along with OS/VS1 and SVS, as a successor to OS/360. It is unrelated ...
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 the different technologies and architectures for
supercomputer
A supercomputer is a computer with a high level of performance as compared to a general-purpose computer. The performance of a supercomputer is commonly measured in floating-point operations per second ( FLOPS) instead of million instructions ...
s and mainframes has led to a so-called
gameframe
A gameframe is a hybrid computer system that was first used in the online game, online video game industry. It is an amalgamation of the different technologies and architectures for supercomputers and mainframe computer, mainframes, namely high c ...
.
See also
*
Channel I/O
In computing, channel I/O is a high-performance input/output (I/O) architecture that is implemented in various forms on a number of computer architectures, especially on mainframe computers. In the past, channels were generally implemented with cus ...
*
Cloud computing
Cloud computing is the on-demand availability of computer system resources, especially data storage ( cloud storage) and computing power, without direct active management by the user. Large clouds often have functions distributed over mul ...
*
Commodity computing Commodity computing (also known as commodity cluster computing) involves the use of large numbers of already-available computing components for parallel computing, to get the greatest amount of useful computation at low cost. It is computing done in ...
*
Computer types
Computers can be classified, or typed, in many ways. Some common classifications of computers are given below.
Classes by purpose
, -
, style="text-align: left;", Notes:
Microcomputers (personal computers)
Microcomputers became ...
*
Failover
Failover is switching to a redundant or standby computer server, system, hardware component or network upon the failure or abnormal termination of the previously active application, server, system, hardware component, or network in a computer net ...
*
Gameframe
A gameframe is a hybrid computer system that was first used in the online game, online video game industry. It is an amalgamation of the different technologies and architectures for supercomputers and mainframe computer, mainframes, namely high c ...
*
List of transistorized computers
This is a list of transistorized computers, which were digital computers that used discrete transistors as their primary logic elements. Discrete transistors were a feature of logic design for computers from about 1960, when reliable transistors ...
*
Master the Mainframe Contest
Master the Mainframe contest is a mainframe programming challenge that is organized annually by IBM Academic Initiative System z.
History
Originally catered to students attending North American institutions of higher learning ( US and Canada, ...
Notes
References
External links
IBM Systems Mainframe MagazineIBM z Systems mainframesIBM Mainframe Computer Support Forum since 2003Univac 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)
{{DEFAULTSORT:Mainframe Computer