Standards like EBCDIC and CGA are on-topic. They are considered retro and are largely obsolete today. However, a consensus about standards that have not stopped being used has not been reached.

Case study: The ¦ button labelling on keyboards

This de-facto standard is wide-spread enough that even Wikipedia has written about it:

Due to historical confusion between the two, computer keyboards and displays may not clearly or consistently differentiate them. [...] in many fonts the vertical bar key produces a broken-bar symbol [...] Some keyboard drivers map the broken bar key to the vertical bar [...] the “> < |” key in the lower left is labelled “> < ¦” but always produces a vertical bar character.

The origins of this standard are less clear - the reasons for this decision (or set of decisions) are interesting if not directly useful.

Case study: ASCII

ASCII is a well-known standard for text representation using 7 bits per character. Whilst now largely superseded by Unicode it remains relevant: not only as the first 128 code-points of Unicode but also remaining useful in its own right, where UTF-8 is too complicated to implement or is otherwise cumbersome.

This standard was extremely useful for ensuring that text remained readable on multiple different machines - for archival purposes and transmission of data between computers, networks or institutions. The various control codes have served (and continue to serve) many different purposes in addition to their intended use.

Are such standards on-topic?

  • 1
    Related: Is retro software still in modern codebases on-topic?
    – wizzwizz4 Mod
    Commented Jun 24, 2017 at 19:39
  • I wouldn't call EBCDIC more obsolete or retro than lets say ASCII. Most Mainframes (under mainframe OS) still use EBCDIC and there's quite some development going on. But I's say both are on topic for Retrocomputing when the question is related to historic issues and/or usage.
    – Raffzahn
    Commented Aug 25, 2017 at 11:42

2 Answers 2


Old Standards questions I personally consider on-topic on this site.

The question you are referring to is, however, off-topic in my opinion for a different reason, because it mixes possibilities and assumptions from new standards (Unicode) with old standards (classic ASCII) - That is off-topic, in my opinion.

  • 2
    That bit about Unicode was only supposed to show how ASCII is still a modern standard. I'll re-add the paragraph break separating the sections.
    – wizzwizz4 Mod
    Commented Jun 26, 2017 at 18:18
  • I don't see how Unicode has anything to do with the referenced question
    – Muzer
    Commented Jun 27, 2017 at 9:30
  • @Muzer ASCII as an "old" standard as no chance to mix up the two characters - It has only room for one of them, but not both. Unicode has.
    – tofro
    Commented Jun 27, 2017 at 10:27
  • @tofro But Unicode and ASCII aren't the only two things that exist. en.wikipedia.org/wiki/ISO/IEC_8859-1
    – Muzer
    Commented Jun 27, 2017 at 10:29
  • @Muzer The IBM PC couldn't use 8859-1. That standard was introduced 1985, the PC 1981. It could have (and maybe has) used EBCDIC, but only some variants of that actually have both characters. Outside IBM, ASCII (or some proprietary encoding) was common for computers up to about 1985
    – tofro
    Commented Jun 27, 2017 at 10:35
  • @tofro en.wikipedia.org/wiki/Code_page_850 . Has a broken bar, contemporary with the IBM PC (in the UK at least), and used in the UK.
    – Muzer
    Commented Jun 27, 2017 at 10:38
  • @Muzer Is that a standard? I thought it was a proprietary IBM PC character encoding.
    – tofro
    Commented Jun 27, 2017 at 10:42
  • @tofro The question (AIUI) is about IBM PC keyboards. They're certainly the only ones where I've seen the swapped pipe/broken bar. And you were the one who said that it couldn't have been ISO-8859-1 because that wasn't contemporary with the IBM PC? The question is asking why PC keyboards based on a design from at least the Model M (possibly the Model F, I couldn't find consistent pictures of UK keyboards) have had these two characters reversed. The Model M was launched in 1984. As you correctly noticed, modern keyboards don't have the issue. This is so totally a retro question in every way.
    – Muzer
    Commented Jun 27, 2017 at 10:42
  • 2
    @Muzer No, It isn't - And that's exactly the point (The question doesn't mention the [IBM] PC anywhere - It's talking about keyboards and standards). Otherwise, I would completely agree with you.
    – tofro
    Commented Jun 27, 2017 at 10:47
  • @tofro OK, then I think that's just a bug with the question. I've certainly not noticed it anywhere besides IBM PC keyboards, clones and derivatives thereof. I certainly wouldn't expect proprietary 80s Micros, for example, to have them.
    – Muzer
    Commented Jun 27, 2017 at 10:48
  • On my desk, there is a Dell laptop, a full sized standard UK keyboard (also Dell) and an Apple laptop with its version of a British keyboard. None of them have | and ¦ swapped.
    – JeremyP
    Commented Jun 27, 2017 at 16:13

I don't see why not. As long as the questions concern understanding of the standard or how it came to be that way or how to use it.

I can foresee questions in this area that would be off topic, or at least borderline. Questions that would be better off on other SE programming sites.

We shouldn't impose a blanket ban.

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