Comments by "Buff Barnaby " (@BigEightiesNewWave) on "ATu0026T Archives: The UNIX Operating System" video.

  1. IBM System/360 still most important development ever in computing, it all still applies to today. System/360 history Contrasting with industry practice of the day, IBM created an entire new series of computers, from small to large, low- to high-performance, all using the same instruction set (with two exceptions for specific markets). This feat allowed customers to use a cheaper model and then upgrade to larger systems as their needs increased without the time and expense of rewriting software. Before the introduction of System/360, business and scientific applications used different computers with different instruction sets and operating systems. Different-sized computers also had their own instruction sets. IBM was the first manufacturer to exploit microcode technology to implement a compatible range of computers of widely differing performance, although the largest, fastest models had hard-wired logic instead. This flexibility greatly lowered barriers to entry. With most other vendors customers had to choose between machines they could outgrow and machines that were potentially too powerful and thus too costly. This meant that many companies simply did not buy computers.
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