# [tex-live] tu-clash

David Carlisle d.p.carlisle at gmail.com
Mon Feb 27 08:56:15 CET 2017

On 27 February 2017 at 01:56, Bob Tennent <rdt at cs.queensu.ca> wrote:
>  >|It's hard to believe that you need a 2.09 format to be honest.
>  >|It would be simpler just to add any macros that need adding to a
>  >|latex209.cfg
>  >|and use latex as normal. If the file really needed a 1980's tex
>  >|distribution
>  >|then you'd need to pull out an archived tex tree from that date, but if
>  >|it runs
>  >|with a current texlive but just using a 2.09 format it's almost certainly
>  >|easier
>  >|to use standard latex and if there are any macros where the 2.09
>  >|emulation isn't good
>  >|enough, to over-ride them in latex209.cfg.
>
> It's a 650-page book with rather complex use of fonts. It's
> far easier to use latex209 than to try to do all that.

OK, you should do whatever works for your document, but for the benefit of
others who might be reading this thread I want to stress that there
are at least three
possible meanings of "using latex2.09" and different pros and cons in each case

For a document such as

\documentstyle{article}
\begin{document}
hello
\end{document}

1)
Just use the document as is with latex.
This is "latex2.09 compatibility mode" If it works it can not take
more than a minute
to convert to latex syntax as compatibility mode really is just a shim
that defines
the old \documentstyle command to do \documentclass and \usepackage as
necessary.

2)
Use the document with a latex209 format made with a latex.tex from an
old release.
in a current tex input tree.
This is _really_ not recommended, it means that you will be using a
2017 article.sty
with a 1992 latex format and be using completely untested and
unsupported code paths.
If it works it works but if for example the format defines a new
command or uses etex
features, and a future article class makes use of that change, a
document using this setup
will stop working. Even if it does not give an error the code paths
are untested and any output
is essentially accidental.

3)
Use a 2.09 format on a dedicated tex input tree with 1990's vintage
versions of all input files.
This is ultimately the best way to ensure compatibility (some people
even archive the binaries
although as time moves on finding a machine to run a 1993 sunos tex
binary gets harder).
In practice this is only recommended for journals or archives that
have thousands of documents
and really the cost of upgrading the system and checking old documents is high.

David