A Brief History of the Mainframe

Contributions from Jim Elliott 

Many folks think that since mainframes have been around for so long, they must be old technology. Nothing could be further from the truth: mainframes have evolved like most technologies, keeping up with and often surpassing other platforms.

This is why the mainframe has been and continues to be used by organizations to host their most important, mission-critical applications. Let’s look back at a brief history of the mainframe, highlighting some of the major developments over the years.

The Early Years

In the 1950s, businesses recognized the potential of computers as flexible, large-scale machines capable of consolidating varied tasks. Over time, there were a number of milestones in the computing world, like the incorporation of solid-state technology and advancements in the scope of data processing. The workhorse mainframe computers that met these demands in turn reshaped how businesses operate, increasing centralization and nourishing new demand.

IBM’s System/360, released in 1964, was revolutionary in that it comprised a whole line of compatible machines, from small to large, which did not require rewriting or even recompiling programs as needs grew. The success of System/360 attracted competition from companies like Burroughs, UNIVAC, NCR, Control Data, and Honeywell (aka “the BUNCH”).

In addition to industries like banking, insurance, and healthcare, the mainframe found another enthusiastic customer in the 1960s: NASA. Mainframes played an important role in space travel, helping NASA solve complex computational problems for space flight, as documented in the recent Hidden Figures movie.

Evolution of the Mainframe

In the early years, mainframes had no interactive interface, but only accepted data and programs on punched cards, paper tape, or magnetic tape. By the early 1970s, mainframes acquired interactive computer terminals (such as the IBM 2741 and IBM 2260) and supported multiple concurrent on-line users along with batch processing.

Throughout the 1970s and 1980s, the mainframe industry continued to flourish, with new software and advancements such as physically smaller machines, continued processor and I/O performance improvements, larger memory, and multiple processors.

Up until the 1990s, mainframes were without question the best option for massive data processing at big organizations. But as other computer technologies advanced and personal computers became more pervasive and popular, analysts began – prematurely and inaccurately – to predict the end of the mainframe. InfoWorld analyst Stewart Alsop famously said in 1991, “I predict that the last mainframe will be unplugged on March 15, 1996.”

IBM, looking toward the future, made a bet that the mainframe way of computing – serious, secure, industrial-strength – would always be in demand, and they released a new mainframe family, the IBM System/390 ES/9000 in 1990 and later the System/390 9672 in 1994. MVS on System/390 was the first certified XPG4 UNIX95 system, paving the way for future UNIX advancements.

The Modern Era

The mainframe has continued to thrive in the modern era, evolving to meet changing business needs and concerns, consistently revered for its stability and reliability. Early in 2000 IBM launched Linux on the mainframe bringing a new world of applications to the platform. IBM’s System/390 was reinvented later in 2000 as the eServer zSeries family with the first 64-bit mainframe, the IBM z900, with high speed connectivity and Capacity on Demand.

Every generation of mainframe hardware and every release of the mainframe operating systems adds advanced function. Examples of this include RAIM memory, HiperSockets, and Out-of-order execution. One of the notable modern systems is IBM’s z13 mainframe line, introduced in 2015 which introduced SMT to IBM mainframes as well as bringing on the industry-standard SIMD vector processing

What’s Next

Most recently, in July 2017 IBM announced a new name for their mainframe products, IBM Z,  and a new generation of mainframes, the IBM z14, that add  improved processor and I/O performance, along with crypto enhancements that enable pervasive encryption of z/OS data sets and Linux file systems. And then in September 2017, IBM launched LinuxONE Emperor II as the latest mainframe-technology enterprise Linux server. As organizations look for increased security, many continue to turn to mainframes for peace of mind.


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