Talk:Analog computer

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First programmable analog computer?[edit]

Why do I keep seeing this same exact line "The castle clock, a hydropowered mechanical astronomical clock invented by Al-Jazari in 1206, was the first programmable analog computer.[10][11][12]" posted on all the major computing history Wikipedia articles? For starters, I believe the claim is a bit sensationalized, as the word "programmable" is being used very loosely here. The term programmable is usually meant in the context of being able to provide instructions to a machine so that the machine can adjust its operations accordingly. In this scenario for Al-Jazari's clock (also very loosely associated with a computer, but it performs a computation of sorts, namely, keeping time and such, so I will grant that I suppose), the clock had to be manually recalibrated. Does this qualify as programmable? In addition to this, the actual cited source isn't even correct. The episode in question of Ancient Discoveries of the History Channel is Series 3 Episode 9, and the episode itself (available on YouTube) doesn't even support the claim that Al-Jazari's clock was the first programmable analog computer. The episode actually makes an even stranger claim: that Al-Jazari's clock was a "super computer". I also looked through source 11 and didn't find the claim supported on the page given. What is going on here? — Preceding unsigned comment added by 2601:82:200:8B20:0:0:0:3C04 (talk) 01:15, 16 June 2022 (UTC)[reply]

Fun story[edit]

This is a bit off topic; if this bothers you stop reading now.

Years ago we had an engineering problem that used a PDB-8 to do a complex calculation. It gave us a correct answer, but was too slow, because the algorithm converged on the answer too slowly. If only we could start with an initial guess that was at least close to the final answer... Analog computer to the rescue! We built up a custom analog computer out of operational amplifiers and high precision hand-selected resistors and capacitors, and used the (inaccurate) answer as our initial guess for the PDP-8. Analog computers pretty much give instant answers. Worked great! --Guy Macon (talk) 23:43, 21 June 2020 (UTC)[reply]

That is an interesting application that would be very useful at Analog computer#Analog–digital hybrids if a reliable source were available. I don't mean a source for that particular device, but a source for the concept in general because many algorithms converge quickly and accurately, but only if they are given a reasonably good guess for an initial starting point. Johnuniq (talk) 10:26, 23 June 2020 (UTC)[reply]

I will do some searching. I am pretty sure that other people did something similar, because the DEC salesman tried to get us to buy a Type 189 low performance analog to digital converter option for the PDP-8 and automate the process instead of reading the answer from the analog computer on an analog voltmeter and typing the numbers in. I did a search and could not find any info on the Type 189 other than that it existed. --Guy Macon (talk) 12:16, 23 June 2020 (UTC)[reply]

ENGVAR[edit]

As it seems to be getting a bit contentious again, can we agree that, given the title of the article, it is indeed in US English? Admittedly as much as "analog" gives me brain leprosy and my editor the red squigglies.

Okay, it'd be nice if ~~Wikipædia~~Wikipedia properly sorted out this problem once and for all but that's another matter and one that isn't happening soon. --Vometia (talk) 14:52, 27 July 2020 (UTC)[reply]

Yes, it looks to me like this one has been stable at American English and American date format for a while. Not clear why the tag was contested. Dicklyon (talk) 15:38, 27 July 2020 (UTC)[reply]

I reverted it because the editor had been marking articles as American English en-masse. The first couple of articles I checked were definitely dubious to claim AmEng but I'm happy to concede on this one if editors here want it. I have to remark though, that I don't consider analog to be defining for AmEng. While analogue is definitely defining for BritEng, analog does occur in British writing. SpinningSpark 16:01, 27 July 2020 (UTC)[reply]

(edit conflict) I agree that this article is in US English, but it is also true that the more commonly used term in the UK is "analog computer" even for speakers who use "analogue" is in other contexts.

I brought this up at Wikipedia:Reference desk/Language#UK or US English. Here is a quote from that discussion:

"My understanding is that in the UK, the American spelling is used in computing contexts; e.g. "program" instead of "programme" but for other uses we revert to the traditional British spelling. So in this case, "analog computer" but in another context, "the human hand is the analogue of a cat's paw". Our English in computing article is silent on the issue however." -- Alansplodge (talk) 20:28, 22 June 2020 (UTC)

From Merriam-Webster:[1]

"The word analogue entered English from French in the 19th century and ultimately traces back to the Greek word logos, meaning "ratio." (The word analogy, which has been a part of English since the 15th century, also descends from logos.) The noun analogue is sometimes spelled analog, particularly when it refers to a chemical compound that is structurally similar to another but slightly different in composition. Adding to the confusion, there is also an adjective spelled analog, which came into use in the 20th century. The adjective can refer to something that is analogous (as in an analog organ), but it is most often used to distinguish analog electronics from digital electronics (as in an analog computer or an analog clock)." (emphasis added)

From Encyclopædia Britannica:[2], [3]

"Analog computer: any of a class of devices in which continuously variable physical quantities such as electrical potential, fluid pressure, or mechanical motion are represented in a way analogous to the corresponding quantities in the problem to be solved. The analog system is set up according to initial conditions and then allowed to change freely. Answers to the problem are obtained by measuring the variables in the analog model. See also digital computer."

"Analogue: in literature, a story for which there is a counterpart or another version in other literatures. Several of the stories in Geoffrey Chaucer’s The Canterbury Tales are versions of tales that can be found in such earlier sources as Giovanni Boccaccio’s Decameron and John Gower’s Confessio amantis. The French medieval beast fable Roman de Renart has analogues in several languages, including Flemish and German. The word is from the Greek análogon, 'to have a relationship' or 'proportional.' "

The template tells us which English variant to use on a page. It does not tell you whether individual phrases are UK English or US English.

The criteria for deciding whether a term is British English or American English is how the term is commonly used in the UK.

So let's look at some statistics. We will start by looking at how a word that everyone agrees is spelled differently in the two English variants: centre/center

The above is what you see when a word is consistently spelled differently in the two English variants.

To get a feel for the limitations of this method, let's try queue/line:

The above does not demonstrate that in the UK a bunch of people waiting is a "line". It simply means that the word "line" also has another, more common meaning in both places.

So, what happens when we try analogue computer/analog computer?

Conclusion: the term "analogue computer" is less popular in the UK than "analog computer", and has been since 1967.

Let's look at some other common engineering terms.

It is clear that in an engineering or computing context the correct usage is "analog" in both English variants with "analogue" being a less-used but still acceptable term in the UK. --Guy Macon (talk) 22:06, 22 June 2020 (UTC)[reply]

--Guy Macon (talk) 16:07, 27 July 2020 (UTC)[reply]

Yes, that'a what I said, but with evidence. SpinningSpark 16:13, 27 July 2020 (UTC)[reply]

Nice evidence. But analogue computer still beats analog computer by a bit in BrE, at least until very recently. The British English 2019 stats seem to be a bit in conflict with your 2012 stats; I hope the update is in fact a refinement, but I have no inside info on this. Dicklyon (talk) 04:56, 28 July 2020 (UTC)[reply]

Babbage?[edit]

Why are Babbage's designs included here as precursors to the analog computer? The difference and analytical engines were digital. -Amcbride (talk) 20:04, 18 January 2022 (UTC)[reply]

I removed the part about Babbage. -Amcbride (talk) 23:05, 19 February 2022 (UTC)[reply]

Turing completeness?[edit]

I removed a link from external links because there was no content to do with the title on the page. I'm not sure if analogue computers can be turing complete at this moment, maybe they can. — Preceding unsigned comment added by 2A02:C7E:2ECA:200:FCBB:7BD1:C6B7:A5A7 (talk) 03:32, 21 December 2023 (UTC)[reply]