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%\centerline{\bf The future of \TeX\ and \MF}
\everypar{\looseness-2}


\title{The future of \TeX\ and \MFb}
My work on developing \TeX, \MF, and Computer Modern has come to
an end. I~will make no further changes except to correct extremely
serious bugs.

I have put these systems into the public domain so that people
everywhere can use the ideas freely if they wish. I~have also spent
thousands of hours trying to ensure that the systems produce
essentially identical results on all computers. I~strongly believe
that an unchanging system has great value, even though it is axiomatic
that any complex system can be improved. Therefore I~believe that it is
unwise to make further `improvements' to the systems called \TeX\
and \MF\/. Let us regard these systems as fixed points, which should
give the same results 100 years from now that they produce today.

The current version number for \TeX\ is 3.1, and for \MF\ it is 2.7.
If corrections are necessary, the next versions of \TeX\ will be 3.14,
then 3.141, then 3.1415, \dots, converging to the ratio of a circle's
circumference
to its diameter; for \MF\ the sequence will be 2.71,
2.718, \dots, converging to the base of natural logarithms. I~intend
to be fully responsible for all changes to these systems for the rest
of my life. I~will periodically study reports of apparent bugs, and
I~will decide whether changes need to be made. Rewards will be paid to
the first finders of any true bugs, at my discretion, but I~can no
longer afford to double the size of the reward each year. Whenever
I~have created a new version, I~will put it in the official master
\TeX\ archive, which currently resides at Stanford University. At the
time of my death, it is my intention that the then-current versions of
\TeX\ and \MF\ be forever left unchanged, except that the final
version numbers to be reported in the `banner' lines of the programs
should become

\centerline{\tt TeX, Version {\char'044}{\char'134}pi{\char'044}}
\noindent and

\centerline{\tt METAFONT, Version {\char'044}e{\char'044}}
\noindent respectively. From that moment on, all `bugs' will be
permanent `features.'

As stated on the copyright pages of Volumes B, D, and E, anybody can
make use of my programs in whatever way they wish, as long as they do
not use the names \TeX, \MF, or Computer Modern. In particular, any
person or group who wants to produce a program superior to mine is
free to do so. However, nobody is allowed to call a system \TeX\ or
\MF\ unless that system conforms 100\% to my own programs, as I~have 
specified in the manuals for the {\tt trip} and {\tt trap} tests. And
nobody is allowed to use the names of the Computer Modern fonts in
Volume~E for any fonts that do not produce identical {\tt tfm} files.
This prohibition applies to all people or machines, whether appointed
by TUG or by any other organization. I~do not intend to delegate the
responsibility for maintainance of \TeX, \MF, or Computer Modern to
anybody else, ever.

Of course I do not claim to have found the best solution to every
problem. I~simply claim that it is a great advantage to have a fixed
point as a building block. Improved macro packages can be added on the
input side; improved device drivers can be added on the output side.
I~welcome continued research that will lead to alternative systems that
can typeset documents better than \TeX\ is able to do. But the authors
of such systems must think of another name.

That is all I ask, after devoting a substantial portion of my life to
the creation of these systems and making them available to everybody
in the world. I~sincerely hope that the members of TUG will help me to
enforce these wishes, by putting severe pressure on any person or
group who produces any incompatible system and calls it \TeX\ or \MF\
or Computer Modern -- no matter how slight the incompatibility might
seem.
\author{Donald E. Knuth}
\bigskip
\centerline{\scaledpicture 46.7pc by 46.5pc (leonardo
scaled 400)}



\endinput


%\centerline{\bf The future of \TeX\ and \MF}
\magnification\magstep1
\baselineskip 12pt
\parskip2pt

\font\logo=logo10 % font used for the METAFONT logo
\font\logobf=logobf10
\def\MF{{\logo META}\-{\logo FONT}}

\def\MFbook{{\sl The {\logosl METAFONT}\kern1pt book}}
\def\TeX{T\hbox{\hskip-.1667em\lower.424ex\hbox{E}\hskip-.125em X}}

\centerline{\bf The future of \TeX\ and {\logobf METAFONT}}
\centerline{Donald E. Knuth}
\bigskip
		[ article as above ]
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