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The mainframe turns 45
The Mainframe: The Dinosaur That Wouldn't Die
By Michael Neubarth
This year marks the 45th anniversary of the IBM mainframe. As Tanapong Ittisakulchai wrote in the Nation in May, "Forty-five years ago, on April 7, 1964, the introduction of the IBM System/360 sparked a revolution in computing and business."
The decision to develop IBM S/360 was a bet-the-company "$5 billion gamble" and the "biggest privately financed commercial project ever undertaken," explained David Pease, an assistant adjunct professor of computer engineering at UC Santa Cruz, in a 2005 coursework presentation.
By the mid-1960s, said Pease, "IBM was in danger of going broke. Meanwhile, IBM's old products were not selling well and there was nothing new to replace them."
Thomas Watson Jr., the son of IBM's founder, who became president of IBM in 1952 and CEO in 1956, is widely quoted as saying, "It was the biggest, riskiest decision I ever made, and I agonized about it for weeks, but deep down I believed there was nothing IBM couldn't do."
As Ittisakulchai noted in the Nation: "It was a massive undertaking of unprecedented scope. In 1964 dollars, IBM invested three-quarters of a billion dollars just on engineering, and another $4.5 billion on factories and equipment. It hired more than 60,000 new employees and opened five major new plants."
Watson's gamble paid off. "System/360 was a huge success," said Pease. "IBM has virtually owned the mainframe computer business since."
"IBM's base of installed computers jumped from 11,000 in early 1964 to 35,000 in 1970, and its revenues more than doubled, to $7.5 billion," wrote John Greenwald in a 1998 article on Thoms Watson Jr. for Time. "At the same time, IBM's market value soared from about $14 billion to more than $36 billion."
Added Ed Scannell in an InfoWorld story from August 2004: "IBM became Big Blue, the color of their early mainframes, by popularizing mainframes with the company's hardware and operating systems -- and eventually its line of applications -- and then gained an iron grip on the entire market for decades."
S/360 Reinvents Computing
The S/360 was a revolutionary advance in computer technology. Before the S/360, experts point out, each computer had a different architecture and operating system, even within the same family line, and each computer was made for specific task, such as data processing and scientific computing.
"Computing was specialized," explained Clipper Group co-founder Mike Kahn in a March 30 article. IBM had at least four different families, with additional ones for the military, said Kahn, noting that, "There were different systems for large and small enterprises, and for North America and the rest of the world."
Peripherals, processors and other components were unique to each system, and there were no standards, said Kahn. "The idea of sharing components between computer lines seemed impractical or impossible, given the different missions of the responsible organizations."
In an April presentation, IBM System z sales specialist Jim Elliott said that because each IBM family of computers "had a different, incompatible architecture," moving from one generation to the next required a migration. Customers, said Elliott, "were getting very frustrated with migration costs that came with processor upgrades."
In addition, noted Pease, customers had to rewrite software for each incompatible larger system, and peripherals had to be replaced with each change to a different IBM model.
"Worse yet," said Kahn, "were the control programs (operating systems). Each was different, and closely tied to the underlying hardware architecture." In retrospect, said Kahn, "prior to System/360 was the Primitive Age of Computing."
The S/360, Kahn explained, solved all of the shortcomings: "System/360 had standard peripheral interfaces, and the offering included a range of attachable tapes, disks, printers, communication devices, terminals, and more, to meet the variety of customers' needs. More importantly, it was a general-purpose machine (capable of both scientific and commercial computing), and capable of running several applications at the same time, with security between applications."
The S/360 family, said IBM's Elliott, was "a wholly new architecture specifically designed both for data processing and to be compatible across a wide range of performance levels." The S/360 line, he explained, was "a family of five increasingly powerful computers that run the same operating systems and can use the same 44 peripheral devices with the same architecture."
The S/360 also introduced the ability to add virtually unlimited storage. According to the IBM Mainframe section of the IBM Archive on IBM's Web site: "Until the advent of the System/360, unlimited storage had been expensive and costly. A certain amount of reprogramming had been necessary to use added core units providing additional memory. With System/360, limited storage capacity was no longer an obstacle to the maximum use of a computer."
Interestingly, the single largest expenditure in the development of the S/360 was the OS/360 operating system, said Pease. Originally estimated at $40 million, the cost to develop OS/360 grew to more than $500 million, and the initial 1 million lines of code ultimately grew to about 10 million, he noted.
Kahn believes that IBM's mainframe software "is really the crown jewel" of the platform. "Almost of all of the black magic that other platforms' operating systems hope to deliver under the banner of 'mainframe-like' descend from this lineage," he said.
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