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Interesting—though I'm not convinced that the IBM approach to generalizing computation would have led us to general purpose computers as we know them now. Sure,

Interesting—though I'm not convinced that the IBM approach to generalizing computation would have led us to general purpose computers as we know them now. Sure, it was more general than what had come before, allowing some parameterization of behavior—but 'more general' and 'universal' may be worlds apart (I don't know enough of the details of IBMs machines to say how much though...). Or even an architecture technically capable of complete generality, but not doing it so well, may be worlds apart from an architecture based on a simple theoretical grounding of that complete generality. Eckert it seems was inspired by Von Neumann whom he worked with on the ENIAC, and Neumann was an early appreciator of Turing's work on universal computation(from 1936)—no surprise that his eponymous architecture mirrors a universal turing machine not only in power but in form (i.e. "the concept of a computer able to store in its memory its program of activities and of modifying that program in the course of these activities"[1]). In view of that, I'm inclined to give similar importance to Turing's theoretical work still. Maybe I'm overestimating the importance of the architectural insights it led to—but I wonder if, say, we even had the Lambda Calculus, but no Turing—would we have fully generally programmable computers as we do now (which are as general in practice as well as in theory, if that makes sense)? I'm not sure... [1] http://www.alanturing.net/turing_archive/pages/Reference%20Articles/BriefHistofComp.html#ACE http://www.alanturing.net/turing_archive/pages/Reference%20A...

Animats 8y ago
Eckert was building working hardware in the early 1930s, long before von Neumann was involved. There was a performance penalty to doing only one thing at a time, the stored program way. Stored programs have a lot of overhead - fetching instructions, decoding instructions, doing instructions that didn't directly do arithmetic - that were not present in the plugboard-wired machines. Those usually did multiple operations on each cycle. When clock rates were a few kilohertz, this mattered, a lot. One result was a split between "scientific" and "business" computers. Scientific computers were usually binary, funded by the military, and were mostly one-off machines in the early days. Business machines were decimal, had to be cost-effective, and were mass produced. The two sides finally came together with the IBM System/360. By that point, both were stored-program. As for an "an architecture technically capable of complete generality, but not doing it so well", that was the IBM 1401, a very successful machine with a very strange architecture. The Computer Museum in Mountain View has two of them working. It was a true stored program computer, quite different from any of the scientific computers. It had a much lower cost and parts count, and ran most of America's middle sized businesses for years.

Animats 8y ago

Eckert was building working hardware in the early 1930s, long before von Neumann was involved. There was a performance penalty to doing only one thing at a time, the stored program way. Stored programs have a lot of overhead - fetching instructions, decoding instructions, doing instructions that didn't directly do arithmetic - that were not present in the plugboard-wired machines. Those usually did multiple operations on each cycle. When clock rates were a few kilohertz, this mattered, a lot. One result was a split between "scientific" and "business" computers. Scientific computers were usually binary, funded by the military, and were mostly one-off machines in the early days. Business machines were decimal, had to be cost-effective, and were mass produced. The two sides finally came together with the IBM System/360. By that point, both were stored-program. As for an "an architecture technically capable of complete generality, but not doing it so well", that was the IBM 1401, a very successful machine with a very strange architecture. The Computer Museum in Mountain View has two of them working. It was a true stored program computer, quite different from any of the scientific computers. It had a much lower cost and parts count, and ran most of America's middle sized businesses for years.