Happy birthday mainframe

7 April marks the 50th anniversary of the mainframe. It was on that day in 1964 that the System/360 was announced and the modern mainframe was born. IBM’s Big Iron, as it came to be called, took a big step ahead of the rest of the BUNCH (Burroughs, UNIVAC, NCR, Control Data Corporation, and Honeywell). The big leap of imagination was to have software that was architecturally compatible across the entire System/360 line.

It was called System/360 to indicate that this new systems would handle every need of every user in the business and scientific worlds because it covered all 360 degrees of the compass. That was a triumph for the marketing team because it would have otherwise been called the rather dull System 500. System/360 could emulate IBM’s older 1401 machines, which encouraged customers to upgrade. Famous names among its designers are Gene Amdahl, Bob Evans, Fred Brooks, and Gerrit Blaauw. Gene Amdahl later created a plug-compatible mainframe manufacturing company – Amdahl.

IBM received plenty of orders and the first mainframe was delivered to Globe Exploration Co. in April 1965. Launching and producing the System/360 cost more than $5 billion, making it the largest privately-financed commercial project up to that time. It was a risky enterprise, but one that worked. From 1965 to 1970, IBM’s revenues went up from $3.6 billion to $7.5 billion; and the number of IBM computer systems installed anywhere tripled from 11,000 to 35,000.

The Model 145 was the first IBM computer to have its main memory made entirely of monolithic circuits. It used silicon memory chips, rather than the older magnetic core technology.

In 1970, the System/370 was introduced. The marketing said that the System/360 was for the 1960s; for the 1970s you needed a System/370. All thoughts of compass points had gone by then. IBM’s revenues went up to $75 billion and employee numbers grew from 120,000 to 269,000, and, at times, customers had a two-year wait to get their hands on a new mainframe.

1979 saw the introduction of the 4341, which was 26 times faster than the System/360 Model 30. The 1980s didn’t have a System/380. But in 1990, the System/390 Model 190 was introduced. This was 353 times faster than the System/360 Model 30.

1985 saw the introduction of the Enterprise System/3090, which had over one-million-bit memory chips and came with Thermal Conduction Modules to speed chip-to-chip communication times. Some machines had a Vector Facility, which made them faster. It replaced the ES/3080

The 1990s weren’t a good time for mainframes. For example, in March 1991, Stewart Alsop stated: “I predict that the last mainframe will be unplugged on March 15, 1996.” Not the most successful prediction, but definitely catching the zeitgeist of the time. It was the decade of the System/390 (back to the old style naming convention). We saw the introduction of high-speed fibre optic mainframe channel architecture Enterprise System Connection (ESCON).

The System/360 gave us 24-bit addressing (32-bit architecture) and virtual storage. The System/370 gave us multi-processor support and then extended storage 24-bit/31-bit addressing. With System/390 we got the OS/390 operating system. As we move into the 2000s, we got zSeries (zArchitecture) and z operating systems giving us 24, 31, and 64-bit addressing. In 2003, the z990 was described as, “the world's most sophisticated server”. In 2005 we got the zIIP specialty engine. In 2008 it was the z10 EC with high capacity/performance (quad core CPU chip). In 2010 the z196 (zEnterprise) had 96-way core design and distributed systems integration (zBX). In 2012, the zEC12 was described as an integrated platform for cloud computing, with integrated OLTP and data warehousing. In 2000 IBM said it would support Linux on the mainframe, and, by 2009, 70 of IBM’s top 100 mainframe customers were estimated to be running Linux. A zEnterprise mainframe can run 100,000 virtual Linux servers. Modern mainframes run Java and C++.  And, the latest mainframe is compatible with the earliest System/360, which means that working code written in 1964 will still run on the latest z12BC.
 
In terms of operating systems, OS/360 was replaced by MVT, which became OS/VS2 SVS, and then OS/VS2 MVS. That became MVS/SE, which became MVS/SP, which became MVS/XA and then MVS/ESA before becoming OS/390 and finally z/OS.

And what does the future look like – with people migrating to other platforms and the technically-qualified mainframers beginning to look quite long in the tooth? The answer is rosey! Mainframe applications are moving from their traditional green screens to displays that look like anything you’d find on a Windows or Linux platform. They can provide cloud-in-a-box capability. They can integrate with other platforms. They can derive information from Big Data and the Internet of Things. Their biggest problem is, perhaps, decision makers at organizations don’t value them enough. Surveys that identify the cost benefits of running huge numbers of IMS or CICS transactions on a mainframe compared to other platforms are generally ignored. Many people think of them as “your dad’s technology”, and high-profile organizations like NASA are unplugging them.

So, although they are often misperceived as dinosaurs, they are in fact more like quick-witted and agile mammals. They provide bang up-to-date technology at a price that is value for money. I predict that we will be celebrating the mainframe’s 60th birthday and its 70th, though we may not be able to imagine how compact it will be by then and what new capabilities it will have.

Happy birthday mainframe.