Managing Memory Dump Files

In typical use, TeX, METAFONT and MetaPost require a large number of macros to be predefined; therefore, they support memory dump files, which can be read much more efficiently than ordinary source code.

For example, LaTeX macros are stored in the file latex.fmt. This file is loaded by pdfTeX, when you start latex.

MiKTeX Options can assist you in defining a new memory dump file:

Click Start → Programs → MiKTeX 2.9 → Maintenance → Settings to open the MiKTeX Options window (see Figure 4.1, “MiKTeX Options: General Settings”).

Click on the Formats tab. You are presented with a list of known memory dump files. To add an entry to this list, click New....

In the Format Definition dialog box, enter the following information:

Format name

The name of the memory dump file without an extension.


The program which creates and loads the memory dump file.

Input file

The name of the main input file.

Preloaded format

Optional: The name of another memory dump file, which must be loaded before the actual memory dump file is being created.


A one-line comment which describes the new memory dump file.

A new executable file with the name of the memory dump will be installed in the MiKTeX bin directory. This executable serves as a short-cut for compiler "&name". For example, these two commands are equivalent:

latex sample2e
pdftex "&latex" sample2e