[looping in TUHS so my historical mistakes can be corrected] Hi Alex, At 2025-02-13T00:59:33+0100, Alejandro Colomar wrote: A. I don't think we know for sure which version of troff was used to format the V10 manual. _Probably_ Kernighan's research version, which was similar to a contemporaneous DWB troff...but what "contemporaneous" means in the 1989-1990 period is a little fuzzy. Also, Kernighan may not have a complete source history of his version of troff, it is presumably still encumbered by AT&T copyrights, and he's been using groff for at least his last two books (his Unix memoir and the 2nd edition of the AWK book). B. It is hard to recreate a Research Unix V10 installation. My understanding is that Unix V8-V10 were not full distributions but patches. And because troff was commercial/proprietary software at that (the aforementioned DWB troff), I don't know if Kernighan's "Research troff" escaped Bell Labs or how consistently it could be expected to be present on a system. Presumably any of a variety of DWB releases would have "worked fine". How much they would have varied in extremely fiddly details of typesetting is an open question. I can say with some confidence that the mm package saw fairly significant development. Of troff itself (and the preprocessors one bumps into in the Volume 2 white papers) I'm much more in the dark. C. Getting a scan out there tells us at least what one software configuration deemed acceptable by producers of the book generated, even if it's impossible to identify details of that software configuration. That in turn helps us to judge the results of _known_ software configurations--groff, and other troffs too. D. troff is not TeX. Nothing like trip.tex has ever existed. A golden platonic ideal of formatter behavior does not exist except in the collective, sometimes contentious minds of its users. Assuming the full source of a document is available, and no part of its toolchain requires software that is unavailable (like Van Wyk's "ideal" preprocessor) then if groff cannot satisfactorily render a document produced by the Bell Labs CSRC, then I'd consider that presumptively a bug in groff. It's a rebuttable presumption--if one document in one place relied upon a _bug_ in AT&T troff to produce correct rendering, I think my inclination would be to annotate the problem somewhere in groff's documentation and leave it unresolved. For a case where groff formats a classic Unix document "better" (in the sense of not unintentionally omitting a formatted equation) than AT&T troff, see the following. https://github.com/g-branden-robinson/retypesetting-mathematics I've opined before that the various aspects of Unix "IP" ownership appear to be so complicated and mired in the details of decades-old contracts in firms that have changed ownership structures multiple times, that legally valid answers to questions like this may not exist. Not until a firm that thinks it holds the rights decides it's worth the money to pay a bunch of archivists and copyright attorneys to go on a snipe hunt. And that decision won't be made unless said firm thinks the probability is high that they can recover damages from infringers in excess of their costs. Otherwise the decision simply sets fire to a pile of money. ...which isn't impossible. Billionaires do it every day. It's the kind of thing I've thought about doing. :) If you do, I very much want to know if groff appears to misbehave. Regards, Branden