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Related to my earlier question about IBM PC cursors, I am now wondering if there has ever been a monospaced character display system (such as a terminal) that would've implemented a vertical cursor in hardware instead of block/underscore cursors we see in 8bits or PC text mode?

Since vertical cursors are now de facto standard in graphical user interfaces, I want to exclude such systems even if they mostly used monospace fonts.

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    You are aware that there is no way to prove that something that could exist doesn't exist and therefor this question can not be answered? [On a side note: The point is not so much about 'Fonts' but fixed wide character cells - back then fonts were something typesetters cared about, but neither computer nor computer users. To create distinguishable fonts one needs space to do so. 5x7 or 8x8 isn't exactly the canvas for a rich 'fonts']
    – Raffzahn
    Oct 5, 2022 at 17:32
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    @Raffzahn: A question of the form "did any X ever exist" may not be answerable in the negative with 100% certainty, but that doesn't make it a bad question, especially since it may be possible to definitively say that various major companies never listed such a thing in any of their catalogs, or to identify some obscure company that did produce such a thing. It may be impossible to prove that there wasn't some obscure company somewhere that produced such a thing, but the other kinds of negative and positive answers may still be useful.
    – supercat
    Oct 5, 2022 at 18:29
  • The answer is probably no but I am to lazy to verify it so I won't write that as an answer... --- I believe the answer is no because of [Text Mode][1] monitors which were the most popular hardware implementation for the display side of terminal don't support vertical cursors. [1]: en.wikipedia.org/wiki/Text_mode
    – Questor
    Oct 5, 2022 at 18:36
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    @Raffzahn yes, after giving this question a bit more thought, I agree and totally see the problem in the wording as such. I'm not sure though if it can be made better by somewhat artificially limiting it to major manufacturers or non-prototype hardware only. I am totally fine to close this question too if it doesn't fit this site, as it well might be unanswerable as such, in case there's no obvious positive for this, either as a full system or as a feature in any of the major chargen/video chipsets of that time.
    – tuomas
    Oct 5, 2022 at 18:54
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    It is hard to imagine an early raster-based terminal using a vertical cursor. Such a feature would involve extra complexity and cost for little practical gain. However, a vector-based terminal might easily have featured a vertical cursor, just as some offered cross-hairs. -- cca.org/vector
    – RichF
    Oct 6, 2022 at 12:30

2 Answers 2

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I am going to suggest a reframe of the entire question.

Before addressing the question of what the earliest cursors looked like, I want to ask what the cursor represented. From the very earliest text editors, there was some ambiguity as to whether the cursor, (usually called the "current location") represented the current character position, or a location between two current characters.
"delete the current character" usually implied that the current location referred to a character position. Likewise "overwrite one character" implied that the current location is a character position.

But "insert a character before the current character" implies that the current location refers to a position "between" two characters, namely the current character and the one just before it (if there is one).

Text editors go all the way back to "Expensive Typewriter" written for the TX0 computer in the late 1950s. This application didn't use the word "cursor", but it had commands that suggest the current location is a character location, and other commands that suggest that the current location is between two character locations.

Next, I'm going to suggest that the block cursor and the horizontal line cursor both visually suggest a character location, while a vertical line cursor visually suggests a position between two characters. Next, I'm going to note that the early "glass TTY" style terminals had no way of putting anything between two character cells, but could put a cursor in a character cell. This argued against using the vertical line, given the above discussion. The early glass TTY terminals were produced in the 1968-1970 timeframe. DEC got into the fray with the VT05 terminal, eventually superceded by the VT52 and the VT100. All of these terminals required a cursor in a character location, and not between two character locations. AFAIK, they all used either horizontal line or block cursors, sometimes user selectable.

So the answer to your question is that probably no large scale manufacturer of glass TTY terminals used a vertical line cursor. But this is only guesswork.

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    In the earliest text editors, used from hardcopy terminals or video terminals used in strict glass-tty mode (no cursor positioning) there was no cursor to worry about. Consequently, in TECO, 'dot' is notionally between characters. 'D' deletes the character after dot; '-D' deletes the character before dot. Of course, once video TECO was invented, the cursor had to be displayed 'after dot'.
    – dave
    Oct 6, 2022 at 12:27
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    Well, a PDP-1 adaptation of Expensive Typewriter used the PDP-1 scope, IIRC. That device was NOT a glass TTY, and would heve been capable of dsplaying a vertical bar in a location between two character cells. Oct 6, 2022 at 13:06
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    You could definitely put a vertical cursor "between" two characters by making it something like a one pixel line at the extreme left (or right) edge of the character block and either overprinting into a screen location if possible, unlikely, or alternating between showing the cursor and the character in the same position, basically a version of a flashing cursor. Whether any old hardware actually did this I don't know, but it was definitely possible. But if you are referring to a very specific piece of hardware then I may have misunderstood and then I'd likely be wrong. Oct 6, 2022 at 14:58
  • Yes, possible, but almost doubling the complexity and expense of the screen manipulation electronics. Oct 7, 2022 at 11:02
  • @WalterMitty: The cost difference between a left-side line cursor and a block cursor would often be a gate. An over-bar cursor (which would appear as an underbar if the vertical connections on the yoke were swapped), however, would be often be cheaper than any kind of cursor that needed to be displayed on multiple scan lines.
    – supercat
    Oct 9, 2022 at 18:41
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It seems like Xerox had such text mode user interface with vertical cursor in 1976.

https://retrocomputing.stackexchange.com/a/25358/4378

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  • I'm very dubious that any of what what referenced in that answer can be described as being terminals. (But I'm old, so "terminal" has the pretty specific meaning of being a simple combo of keyboard, control circuitry, and CRT that displays text in fixed (usually) 24x80 cells and is connected by wire to a central server.
    – RonJohn
    Oct 9, 2022 at 8:46
  • Even though it's using a monospaced font for it's text UI, the Alto is very much not a "monospaced display system" in terms of its hardware. Oct 9, 2022 at 9:43

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