NFSS was an extension to LaTeX written by Frank Mittelbach and Rainer Schöpf. It is described in TUGboat 10(2). In traditional typesetting, fonts are described by four parameters: the family (e.g., computer modern), the series (i.e., the weight and width of the font, such as light or bold), the shape (e.g., italic), and the size. NFSS is a mechanism allowing the user to change any of these independently. NFSS makes it relatively easy to use nonstandard fonts such as the PostScript ones with LaTeX, and easy to change maths fonts. It also allows dynamic loading of fonts at runtime (i.e., not when the format file is created).
With the demise of LaTeX 2.09 as supported software, the label `NFSS' has become somewhat misleading, as there's no `old' scheme with which to contrast it - LaTeX has incorporated the NFSS.
LaTeX2e is the version of LaTeX prepared and supported by the LaTeX3 project team. With the advent of LaTeX2e, users gained a formal support structure, and the knowledge that bug fixes would be incorporated into the distribution on a fairly regular basis (new releases appear at approximately 6-month intervals).
LaTeX2e is so structured that significant enhancements may be added using macro add-ons, rather than by the different TeX formats that were the bane of the LaTeX 2.09 world.
LaTeX2e is upwardly compatible with LaTeX 2.09, but has new features. In the latest (December 1998) release, these include:
\caption without being protected.
\newcommand can define commands with one optional argument;
such commands are automatically robust.
The LaTeX3 project team (see http://www.latex-project.org/latex3.html) is a small group of volunteers whose aim is to produce a major new document processing system based on the principles pioneered by Leslie Lamport in the current LaTeX. It will remain freely available and it will be fully documented at all levels.
The LaTeX3 team's first product, LaTeX2e, was delivered in 1994, and the team undertakes its maintenance.
Omega
is a program built as an extension of the TeX sources which works
internally with 16-bit
characters (Unicode); this allows it to work with most scripts in the
world with much reduced coding scheme complications. Omega also has a
powerful concept of input and output filters to allow the user to work
with existing transliteration schemes, etc. Omega is an
ongoing project by John Plaice (plaice@cse.unsw.edu.au) and
Yannis Haralambous (Yannis.Haralambous@univ-lille1.fr). An
email discussion list is available: subscribe by sending a message
`subscribe omega <your name>' to listserv@ens.fr
The base distribution of Omega was released in November 1996; it is available via systems/omega
Implementations of Omega are available as part of the teTeX, mikTeX, fpTeX and CMacTeX distributions (see the question on TeX systems).
The NTS project first saw the light of day at the Hamburg meeting of DANTE during 1992, as a response to an aspiration to produce something even better than TeX. The project is not simply enhancing TeX, for two reasons: first, that TeX itself has been frozen by Knuth (see the future of TeX), and second, even if they were allowed to develop the program, some members of the NTS team feel that TeX in its present form is simply unsuited to further development. While all those involved in the project are involved with, and committed to, TeX, they recognise that the end product may very well have little in common with TeX other than its philosophy.
Initially, and despite the reservations expressed at the inaugural meeting, the group is concentrating on extending TeX per se: members are implementing extensions and enhancements to TeX through the standard medium of a change-file. These extensions and enhancements, together with TeX proper, form a system called e-TeX, which is 100% compatible with TeX; furthermore, it is possible during format creation to construct a format that is TeX: no extensions or enhancements are present.
The final aim of the project will be to produce an entirely new typesetting system, building on the experience gained in the earlier phases. This system is intended to provide a stable basis for typesetting in the future, in the way that TeX has since it was first offered to the world.
A distribution of e-TeX was made available in November 1996. It is available via systems/e-tex; e-TeX is also distributed on the TeX Live CD-ROM (see TeX CD-ROMs).
PDFTeX (formerly known as TeX2PDF) arose from Han The Thanh's post-graduate research at Masaryk University, Brno, Czech Republic. The basic idea is very simple: to provide a version of TeX that can output PDF as an alternative format to DVI. PDFTeX implements a small number of new primitives, to switch to PDF output, and to control various PDF features. Han The Thanh is continuing work on the project; the latest version is available from systems/pdftex, and a version was distributed on the TeX Live CD-ROM (see TeX CD-ROMs).