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While Knuth has declared that TeX will never
change in any substantial way
, there remain
things that one might wish had been done differently, or indeed
implemented at all.
The NTS project set out to produce an advanced replacement for
TeX, to provide a basis for developing such modifications: this
“New Typesetting System” would share Knuth’s aims, but would
implement the work in a modern way taking account of the lessons
learned with TeX. While a first demonstrator NTS did
appear, it wasn’t practically useful, and the project seems no longer
In parallel with its work on NTS itself, the project developed
a set of extensions that can be used with a (“true”) TeX system.
Such a modified system is known as an e-TeX system, and the concept
has proved widely successful. Indeed, current TeX distributions
are delivered with most formats built with an e-TeX-based system (for
those who don’t want them, e-TeX’s extensions can be disabled, leaving
a functionally standard TeX system).
The extensions range from the seemingly simple (increasing the number
of available registers from 256 to 32768) through to extremely subtle
has required e-TeX for its operation
for some time, though development is now focused on the use of
Some LaTeX packages already specify the use of e-TeX. Some such
packages may not work at all on a non-e-TeX system; others will
work, but not as well as on an e-TeX system. The
has announced that future LaTeX
packages (specifically those from the team, as opposed to those
individually contributed) may require e-TeX for optimum performance.
- systems/e-tex (or browse the directory); catalogue entry
This answer last edited: 2011-07-13
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This is FAQ version 3.27, released on 2013-06-07.