Introduction
===================

This manual is intended for many different audiences.
Typically a particular reader will only need to be concerned with a small portion of this guide, but there are a number of cross-references between sections.
This manual assumes some familiarity with Mark5 units, Linux, and the general way in which a VLBI correlator is used.
The following topics are discussed: running DiFX, coexistence issues with the VLBA hardware correlator, explanation of various file/document types, and detailed installation instructions.
This manual covers DiFX version 2.5 and periodically will be updated to current with DiFX improvements.
Please report any errors that are found in this manual to ``wbrisken@nrao.edu`` or to the DiFX developers mailing list ``difx-developers@nrao.edu``.

Notation
-----------------

Text written in ``typewriter`` font represents literal text and is to be transcribed verbatim when typing and text in ``italics`` is to be substituted with other text, such as the specific value of the named variable.
To be consistent with this notation, all mention of programs by name or filenames (and portions thereof) are written in ``typewriter`` font.