Abstract:

This presentation by Thierry Laronde introduces kerTeX, his modern and highly portable distribution of Donald Knuth's TeX typographic system. Laronde aims to dispel common misconceptions about TeX on Plan 9, asserting that kerTeX is a fully up-to-date and first-class citizen across various operating systems, including Plan 9, Linux, Android, and Windows (via WSL). He emphasizes kerTeX's minimal dependencies, relying solely on libc for runtime, with POSIX.2 utilities used only for compilation to ensure cross-platform consistency.

A significant part of the talk clarifies the distinction between the TeX interpreter and its common instantiations like "tex" or "latex," which are byte-compiled versions of macro sets for efficiency. Laronde then draws a detailed comparison between TeX and troff, arguing that TeX is a more general and powerful interpreter capable of eventually replacing troff for system typography and manual page rendering due to its robustness and extensibility, particularly through his pro engine. The overarching philosophy behind kerTeX aligns with Knuth's original goal of long-term reproducibility and consistency across different computing environments.

Summarizing "Thierry Laronde - TeX: from a typographic system to the typography of the system"

• 0:01 Introducing kerTeX: Thierry Laronde, creator of kerTeX, clarifies that TeX on Plan 9 is a first-rate, up-to-date system, directly addressing misunderstandings.
• 1:21 Cross-Platform Portability: kerTeX is designed to be available across various OS, including Android, Linux, BSD, Plan 9, and Windows (via WSL). POSIX.2 utilities are used only for compilation across this wide range of systems, not for runtime.
• 3:06 Minimal Dependencies: The core TeX engine (as part of kerTeX) relies solely on the libc (standard C from 1989/1990), ensuring extreme portability.
• 3:42 TeX as an Interpreter & DVI Output: TeX is an interpreter that processes input, ignoring end-of-lines, to produce device-independent (DVI) layout files for pages. DVI is then post-processed (e.g., DVI to PostScript via dvips).
• 5:41 The "TeX" Torture Test: An engine can only be called "TeX" (uppercase) if it passes Donald Knuth's rigorous torture test, ensuring consistent and precise output.
• 6:37 TeX Engine vs. tex/latex Commands: The common tex or latex commands are not separate programs but are instances of the TeX interpreter (virtex) pre-loaded with "digested" (byte-compiled) sets of macros for faster processing. latex is a huge set of macros, not an engine itself.
• 10:47 TeX vs. troff: troff is also an interpreter but lacks byte-compiling, constantly rereading files. It also lacks a "torture test" and is less general than TeX. Laronde argues that TeX can emulate and eventually replace troff as a page creator by using troff-like macro sets.
• 13:57 Consistency Across Systems: A core goal of kerTeX is to provide an identical user experience for TeX regardless of the underlying operating system, allowing users to swap systems (e.g., to Plan 9) without noticing a difference in utilities or commands.
• 18:03 The pro Engine: As LaTeX evolved and required more extensions (like epsilon-TeX), Laronde developed pro (Prote), an extension of the TeX engine that is compatible with all modern LaTeX primitives. In kerTeX, pro serves as the single, underlying engine, which is small, libc-only, and highly portable.
• 24:00 Knuth's Motivation for TeX: Donald Knuth developed TeX, Metafont, and designed fonts to ensure his "Art of Computer Programming" could be precisely reproduced even centuries later, regardless of evolving printing technology.
• 26:11 TeX as a Complete Solution: Laronde envisions TeX as a completely self-contained system capable of generating page layouts (DVI), drawing fonts (Metafont), and creating figures (Metapost), reducing reliance on external, complex, and potentially licensed software like Ghostscript.
• 30:39 DVI for All Output: The DVI format is central; Laronde plans to extend DVI and develop post-processors to generate various outputs, including plain text for terminals, from the DVI layout.
• 33:27 Progress on MS Macros & Hint Format: While converting troff's MS macros for TeX is not yet complete, Laronde believes it could be done within a month with dedicated effort and welcomes help. He notes that the Hint reflowable text format is based on his pro engine's macros.
• 35:53 TeX's Generality & kerTeX Audience: TeX is more general than troff and can emulate its functionality. kerTeX is intended for everyone – academia, personal users, and commercial entities, as its licensing (BSD, MIT for pro, open for Knuth's work) permits broad use.