[drfuchs]

Not so about the Linotype. Back in 1980, I personally ran the Alphatype CRS phototypesetter (bought by DEK for the purpose), in the basement of Margaret Jacks Hall, that produced the entire camera-ready copy of The Art Of Computer Programming, Volume II, Second Edition. The DVI files and Computer Modern fonts were created by the early, Sail-language, 36-bit versions of TeX and Metafont that were later redesigned and implemented to be more cross-platform. Knuth rewrote the firmware that resided on the Alphatype (in 8080 assembly language), and I wrote the code that translated from DVI and drove it from the DEC20 mainframe over a serial line (trickier than it sounds; see our joint paper "Optimal prepaging and font caching" ACM TOPLAS Vol 7 Issue 1).

[wolfi1]

impressive. do you have written up that somewhere? I'm sure there are several people interested in the history of Metafont, TeX, etc.

[drfuchs]

Earlier additional great info from svat (and ramblings by me) are at https://news.ycombinator.com/item?id=20006525

One point concerning Metafont and Computer Modern (and TeX): A key overall goal of the whole kit and caboodle is that a document written in TeX and using the default fonts would produce exactly the same output on all capable computers and output devices, indefinitely into the future, with the same line breaks, page breaks, character shapes, etc. And in fact TeX files from over half a century ago still produce pixel-perfect results.

This requirement meant that the default fonts had to be portable between printers and typesetters with various resolutions (and other optical filtering attributes). There was simply no other way at the time to accomplish this than using a tool like Metafont to author a home-grown font family like Computer Modern (and even then it was a bit of a hope and a prayer).

And don't even get me started on how 5pt super-super-scripts aren't just 10pt characters scaled down by half, contrary to how post-hot-lead typesetters operated, and not fully addressed commercially until decades later.

[wolfi1]

thanks for the pointer, were you one of the two students tasked with writing the program during DEK's stay in China? As you mention the problem of smaller fonts it seems font hinting was an invention of the nineties, how did you solve it?

[drfuchs]

Nope, that would be Michael Plass (thesis title: "Optimal pagination techniques for automatic typesetting systems," though his line-breaking work is what showed up in TeX) and Frank Liang ("Word Hy-phen-a-tion by Com-put-er"). I wasn't there yet.

Metafont users can specify point size, boldness, slant, and whatever other parameters they choose (plus device-specific info like resolution) that can then be used in the simultaneous equations that determine the coordinates of critical points and shapes of pens used to draw the characters. So, for the smaller-font issue, the width of the pen may be a non-linear function of the font point size; ditto for the x-height, etc. In Metafont, it's the responsibility of the font designer / coder to handle it all; there's no automated algorithmic monkeying with the pixels other than what you write. This all becomes much clearer with a perusal of The METAFONTbook.

[WillAdams]

I'm pretty sure there are TUGboat articles on this, but you may find:

https://tug.org/interviews/fuchs.html

a useful starting point.