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How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

cs.princeton.edu

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Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#61

Post by weinzierl »

laserbeam wrote: post #29
coliveira wrote: post #3

It seems that the author never used a typewriter! The typewriter has tabs, so that you can center the equal sign, for example, after 3 tabs, and the alignment will be perfect each time. Most probably Dennies Richie sent his manuscript to a professional typist who provided services to the university, unless he was adept at spend several hours typing until he got professional results.

As far as I understand, the author argues the typewriters of the era couldn't do that. I have no knowledge about what typewriters existed back then, but any criticism of that claim should also be specific to the time period and not just typewriters in general. (I find it plausible that typewriters in the 60s had the feature you describe, it's just not clear). For the use of whiteout, for example, the date claim is mu…

Having used a typewriter I can confirm what raphlinus wrote above.

Moreover you would not have to use tabs necessarily. A typewriter is an analogue device with a roller on a sled. It's not that there are fixed character cells like in a computer. When you press a button the roller usually moves a fixed distance but you can suppress that and position the roller freely. You also can position your characters freely in the vertical direction by turning the roller with a knob on its side. Basically characters could be placed on the sheet without restrictions. To get an idea what was possible look up Typewriter Art.

Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#62

Post by tromp »

The Wikipedia page on LOOP [1] contains an excellent overview of the very simple language that is the subject of Dennis' thesis, and that turns out to be equivalent in expressive power to primitive recursive functions.

Curiously, one of the instructions in Dennis' original formualtion, namely the assignment X = Y of the value in one register to another, turns out to be redundant, as it it also achieved by

    X = 0
    LOOP Y
      X = X + 1
    END
Btw, this example shows the entire repertoire of instructions available in LOOP, namely set to 0, increment, sequential composition, and looping. The method of obtaining a predecessor function

    TMP = 0
    LOOP X
      Y = TMP
      TMP = TMP + 1
    END
reminds me of a similar solution for the Church numerals in lambda calculus [2].

[1] https://en.wikipedia.org/wiki/LOOP_(programming_language)

[2] https://en.wikipedia.org/wiki/Church_encoding#Derivation_of_...

Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#64

Post by newaccount74 »

Animats wrote: post #17

This is a non-mystery. It looks like this was done with a Selectric typewriter using two typeballs, one of them "Symbols 10", and the other for text.[1] The reason there are two versions of "4" is because you could type something like "(4.10)" with either the regular typeball or the Symbols ball. Both have numbers, parentheses, upper case letters, and a period/decimal point. Switching typeballs takes a few seconds, s…

The correction mentioned in the article ("appreciations" instead of "applications") also makes it sound very plausible that the text was typed by someone other than the author himself.

Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#65

Post by canadianfella »

qart wrote: post #40
userbinator wrote: post #14

We have no idea how it would even be possible to make these horizontal adjustments with the typing machines of the time. I agree with the other comment here that the authors haven't used a typewriter, or at least in enough detail to know that on many if not all of them, holding down the spacebar will advance the carriage by half a character (and releasing it, in normal use, advances the other half.)

I recognized the names of two of the authors immediately, David F. Brailsford, and Brian W. Kernighan. Not only are they both contemporaries of Ritchie, but Kernighan was a close colleague too.

[dead]

Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#66

Post by fsckboy »

userbinator wrote: post #14

We have no idea how it would even be possible to make these horizontal adjustments with the typing machines of the time. I agree with the other comment here that the authors haven't used a typewriter, or at least in enough detail to know that on many if not all of them, holding down the spacebar will advance the carriage by half a character (and releasing it, in normal use, advances the other half.)

> holding down the spacebar will advance the carriage by half a character (and releasing it, in normal use, advances the other half.)

backspace did something similar, it was a common error correction to reposition the carriage halfway between two letters to sqeeze-in/add a letter that had been missed (once you get used to computers it's hard to remember that backspace didn't delete anything, it just moved you back)

Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#68

Post by ricksunny »

AlphaGeekZulu wrote: post #59

I have not done any research in Ritchie's PhD thesis, but just as a general hint on the research: besides typewriters there were of course (foto-)typesetting systems at the time capable of producing the output. The Berthold Diatype, for example, dates back to 1952 and would have been able to produce the formulars. It would have required painstaking preparation and a very experienced typesetter - but, possible. Intere…

>Sometimes it only requires a personal relation to make something seemingly impossible happen.

That's a very empowering anecdote & story, thank you for sharing it :)

Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#69

Post by dmcq2 »

Reading it the obvious way I'd have done the job at the time would be to do two or even four prints on each page selecting which chracers fell on that gride each time. The thesis would be written using LISP to do the formatting. This would also only print those characters that fell on the current alignment. It would be a bit fiddly making the 1/24 inch alignments of the pages and I'm sure there would have been plenty of mistakes! But it is straightforwardly doable with the tools he had. Very impressive though. If he did have a LISP program like that I'd have expect him to have developed it further or make some mention of it.

Re: How did Dennis Ritchie produce his PhD thesis? A typographical mystery (2022) [pdf]

#70

Post by K0balt »

Nothing about his thesis suggests that it was done using anything except a typewriter and some engineering (drafting)stencils in common use at the time. Typewriters are capable of arbitrary character alignment (and even rotation with clever abuse of the paper) and engineering stencils were in common usage for all common symbolic figures.

I have produced documents with similar and more complex features using those tools, and Ritchie’s accuracy, although more than sufficient, is unremarkable for someone adept with those tools.

In the analog world, the mechanical and repetitive default spacing of the typewriter was the intrusion, not the ontological rule.

The re-production of the document in its various iterations is remarkable, but consistent with using a layout table (written notes of calculated alignments). It was a common method used to calculate the original spacing for awkward or critical text. You couldn’t just type something and then move it, so you would work it out ahead of time before typing. If you were smart or experienced you would note these calculations as a list of alignments so you could reuse them when you inevitably had to start over. There is no reason to suspect that these alignment notes would not have been reused and iterated upon.

He might easily have done this himself, and certainly would not have found it difficult to find someone with the skills to do so. The fact that most people didn’t bother speaks more to the perceived importance of doing so rather than the physical capability to produce the work artfully using common tools.

He either considered it important to do it somewhat artfully or someone helping him did. It’s no more complex than that.

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