I understand the point they're making but it's wrong: a computer doesn't have to be universal, to be a computer, neither does having a fixed program, like the Antikythera mechanism, disqualify a device from being a computer. In the same sense, Turing Machines are not necessarily universal; Universal Turing Machines are. But there's no official or formal definition of what a "computer" is and the category is less crisp than the author is trying to make it.

In the same way drawing a line between programmable and fixed-program computer is arbitrary and in fact the author spends much of the article dismissing Babbage's Analytical engine, which was a programmable computer, on the grounds it wasn't actually built; which is, of course, irrelevant, because a physical machine is not necessary for complete computation, as demonstrated by Ada Lovelace.

In any case, the early days of modern computing (1930's- 1940's) were replete with a plethora of computing machinery of various architectures many of which were called "computers", without them being necessarily programmable computers; for example, the "Atanassoff-Berry Computer" [1].

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[1] https://en.wikipedia.org/wiki/Atanasoff%E2%80%93Berry_comput...