TeX is a powerful, flexible typesetting system used by thousands of people around the world. It is extremely portable and runs on dozens of operating systems. One unfortunate consequence of TeX's flexibility is that there is no single ``right'' way to install it. This has resulted in hundreds of different installed configurations.
The primary purpose of this document is to describe a standard TeX Directory Structure (TDS) for macros, fonts, and other such implementation-independent TeX files. As a matter of practicality, this document also suggests ways to incorporate the rest of the TeX files into a single structure. In the not-so-long run a consistent directory structure will make it much easier to install and maintain TeX. We hope that administrators and developers of both free and commercial implementations of TeX will adopt this standard. It has been designed to work on all modern systems. In particular, this Technical Working Group (TWG) believes it is usable under Unix, MS-DOS, OS/2, MacOS, and VMS.
This document is intended both for the TeX system administrator at a site and for people preparing TeX distributions---everything from a complete runnable system to a single macro or style file. It will also help TeX users find their way around systems organized this way.
The role of the TDS is to stabilize the organization of TeX-related software packages that are installed and in use, possibly on multiple platforms simultaneously.
At first glance, it may seem that the CTAN archives fulfill (at least) part of this role, but this is not the case. The role of the CTAN archives is to simplify archiving and retrieval of packages, not their installation and use.
In fact, the roles of the TDS and CTAN are frequently in conflict, as you will discover as you read this document. For distribution in CTAN, it's useful to combine many different types of files into a single unit; for use, it is traditional to segregate files (even similar files) from a single package into separate, occasionally distant, directories.