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The History of Computing

199 EpisodesProduced by Charles EdgeWebsite

Computers touch all most every aspect of our lives today. We take the way they work for granted and the unsung heroes who built the technology, protocols, philosophies, and circuit boards, patched them all together - and sometimes willed amazingness out of nothing. Not in this podcast. Welcome to th… read more


The IBM System/360

Welcome to the History of Computing Podcast, where we explore the history of information technology. Because understanding the past prepares us for the innovations of the future! Todays episode is about the IBM System/360. System/360 was a family of mainframes. IBM has done a great job over the decades following innovations rather than leading them, but there might not be another single innovation that was as influential on computing as the System/360. But it’s certainly hard to think of one. IBM had been building mainframes with the 700 and 7000 series of systems since 1952, so they weren’t new to the concept in 1964 when the S360 was announced (also when Disney released Mary Poppins and ). But they wanted to do something different. They were swimming in a red ocean of vendors who had been leading the technology and while they had a 70 percent market share, they were looking to cement a long-term leadership position in the emerging IT industry. So IBM decided to take a huge leap forward and brought the entire industry with them. This was a risky endeavor. Thomas Watson Jr, son of the great IBM business executive Thomas Watson Sr, bet the proverbial farm on this. And won that bet. In all, IBM spent 5 billion dollars in mid-1960s money, which would be $41B today with a cumulative 726.3% rate of inflation. To put things in context around the impact of the mainframe business, IBM revenues were at $3.23 B in 1964 and more than doubled to $7.19 B by 1970 when the next edition, the 370, was released. To further that context, the Manhattan Project, which resulted in the first atomic bomb, cost $2 B. IBM did not have a project this large before the introduction of the S360 and has not had one in the more than 50 years since then. Further context, the total value of all computers deployed at the start of the project was only $10B. These were huge. They often occupied a dedicated room. The front panel had 12 switches, just to control the electricity that flowed through them. They had over 250 lights. It was called “System” 360 because it was a system, meaning you could hook disk drives, printers, and other peripherals up to them. It had 16 32 bit registers and four 64 bit floating point registers for the crazy math stuffs. The results were fast, with over 1000 orders in the first month and another 1000 by years end. IBM sales skyrocketed and computers suddenly showing up in businesses large and small. The total inventory of computers in the world jumped to a $24B value in just 5 years. A great example of the impact they had can be found in the computer the show Mad Men featured, where the firm got an S360 and it served as a metaphor for how the times were about to change - the computer was analytical, where Don worked through inspiration. Just think, an interactive graphics display that let business nerds do what only computer nerds could do before. This was the real start to “data driven” decision making. By 1970 IBM had deployed 35k mainframes throughout the US. They spawned enough huge competitors that the big mainframe players were referred to as Snow White and the 7 dwarfs and later just “The Bunch” which consisted of Burroughs, NCR, Control Data, Honeywell, and the Univac Division of Sperry Rand. If you remember the earlier episode on Grace Hopper, she spent some time there. Thomas Watson Jr. retired the following year in 1971 after suffering a heart attack, leaving behind one of the greatest legacies of anyone in business. He would serve as an ambassador to Russia from 79 to 81, and remain an avid pilot in retirement. He passed away in 1993. A lot of things sell well. But sales and revenue aren’t the definition that shapes a legacy. The S360 created so many standards and pushed technology forward that the business legacy is almost a derivative of the technical legacy. What standards did the S360 set? Well, the bus was huge. Stndardizing I/O would allow vendors to build expansion and would ultimately become the standard later. The 8-bit byte is still used today and bucked the trend of accessing variable sized arbitrary bit addressing. To speed up larger and larger transactions, the S360 also gave us Byte-addressable memory with 24 bit addressing and 32-bit words. The memory was small and fast with control code stored there permanently, known as microcode memory. This meant you didn’t have to hand wire each memory module into the processor. The control store also lead to emulators, as you could emulate a previous IBM model, the 1401, in the control store. IBM spent $13 M on the patent for the tech that came out of MIT to get access to the best memory on the market. The S360 made permanent store a main-stay. IBM had been using tape storage since 1952. 14 inch disk drives were smaller than 24 inch disk drives used in previous models, had 100x the storage capacity and accessed data 10 times faster. The S360 also brought with it new programming paradigms. We got hexadecimal Floating Point Architectures. These would be important to New Drug Applications to the FDA, weather predicting, geophysics, and graphics databases. We also got Extended Binary Coded Decimal Interchange Code or EBCDIC for short is character encoding in the 8th bit. This came from moving punch cards to persistent storage on the computers. That 8th bit was from two zone and number punches on cards which made up two bits and another to indicate a small s or a large S. EBCDIC was not embraced by the rest of the computer hacker culture. One example was: "So the American government went to IBM to come up with an encryption standard, and they came up with… EBCDIC!" ASCII has mostly been accepted as the standard for encoding characters (before and after EBCDIC). Solid Logic Technology (or SLT) also came with the S360. These flip chip-mounted packages contained transistors, diodes and resistors in a ceramic substrate that had sockets on one edge and could be plugged into the backplane of a computer. Think of these as a precursor to the microchip and the death of vacuum tubes. The central processor could run machine language programs. It ran OS/360, officially known as IBM System/360 Operating System. You could load programs written in COBOL and FORTRAN with many organizations still running code written way back then. The way we saw computers and they way they were made also changed. Architecture vs implementation was another substantial innovation. Before the S360, computers were built for specific use cases. They were good at business and they were good at business or they were good at science. But one system wasn’t typically good at both tasks. In fact, IBM had 7 mainframe lines at this point, sometimes competing with each other. The S360 allowed them to unify that into the size and capacity of a machine rather than the specific use case. We went from: “here’s your scientific mainframe” or “here’s your payroll mainframe” to “here’s your computer”. But the Model 30 was Introduced in 1965, along with 5 other initial models, the 40, 50, 60, 62, and 70. The tasks were not specific to each model and a customer could grow into additional models, or if the needs weren’t growing, could downgrade to a lower model in the planned 5 year obscelence cycle that computers seem to have. Given all of this, the project was huge. So big that it led to Thomas Watson forcing his own brother Dick Watson out of IBM and moving the project to be managed by Fred Brooks, who worked with Chief Architect Gene Amdahl. John Opel managed the launch in 1964. In large part due to his work on the S360 project, Brooks would go on to write a book called The Mythical Man Month, which brought us what’s now referred to as Brooks’ Law, which states that adding additional developers does not speed up a software project, but instead makes it take longer. Amdahl would go on to found his own computer company. In all, there were twenty models of the S360, although only 14 shipped - and IBM had sold 35,000 by 1970. While the 60 in S360 would go on to refer to the decade and the follow-on S370 would define computing in the 70s, the S360 was sold until 1978. With a two-thirds market share came anti-trust cases, which saw software suddenly being sold separately and leasing companies extending that 5 year obscelecence - thus IBM leassors becoming the number one competition. Given just how much happened in the 13 year life of the System/360, even the code endures in some cases. The System Z servers are still compatible with many applications written for the 360. The S360 is iconic. The S360 was bold. It set IBM on a course that would shape their future and the future of the world. But most importantly, before the S360 computers were one thing used for really big jobs - after the S360, they were everywhere and people started to think about business in terms of a new lexicon like “data” and “automation.” It lead to no one ever getting fired for buying IBM and set the IT industry on a course to become what it is today. The revolution was coming no matter what. But not being afraid to refactor everything in such a big, bold demonstration of market dominance made IBM the powerhouse it is even today. So next time you have to refactor something, think of the move you’re making - and ask yourself What Would Watson Do? Or just ask Watson.

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