Wolfram System File Organization

Wolfram System Distribution Files

A full Wolfram System installation consists of thousands of separate files, arranged in several hundred directories under the main installation directory. The location of the main installation directory is determined at install time. From within a Wolfram Language kernel, its name is given by the value of $InstallationDirectory.

C:Program FilesWolfram ResearchMathematica12.0Windows

Default locations for the Wolfram System installation directory.

The executable programs that launch the Wolfram System are typically in the main installation directory. Sometimes there may also be links to them, or scripts accessing them, in other locations. From within a Wolfram Language kernel, First[$CommandLine] gives the full name of the executable program corresponding to that kernel.

MathematicaWolfram System front end
WolframKernelWolfram Language kernel, usually with its own text-based interface
wolframWolfram Language kernel to be run in a terminal or shell
mccscript for preprocessing and compiling WSTP C source files

Typical executable programs accessible from the installation directory.

The main installation directory has three standard subdirectories that contain material distributed with the Wolfram System. Under normal circumstances, none of the contents of these directories should ever be modified, except, for example, if you choose to edit a shared stylesheet.

AddOnsbundled Wolfram System add-ons
DocumentationWolfram Language documentation
SystemFilesWolfram System files

Toplevel subdirectories of the main installation directory.

Particularly on Linux systems, the Wolfram System often has executable files for different computer architectures and systems stored in a single overall directory structure. Each system is in a subdirectory with a name given by $SystemID. Some resource directories may also contain files specific both to particular languages and particular computing environments. These files are given in subdirectories such as Japanese/Windows.

Kernel/Binaries/systemkernel binaries or elements for each computer system
Kernel/SystemResources/systemsystem-specific .mx files used by the kernel
Kernel/TextResourcesmessage and text files used by the kernel
FrontEnd/Binaries/systemfront end binaries or elements for each computer system
FrontEnd/SystemResourcesfiles used by the front end in each window system environment
FrontEnd/TextResourcesmessage and text files used by the front end
FrontEnd/StyleSheetsdefault notebook stylesheets
FrontEnd/Palettesdefault palette notebooks
Libraries/systemWSTP and other libraries used by the kernel and front end
Linksdeveloper kits for WSTP and other connection technologies
FontsWolfram System fonts, often copied to a central directory
CharacterEncodingsspecifications of character encodings
SpellingDictionariesspelling dictionaries
SystemDocumentation/envLinux man pages and other environment-specific documentation
Graphics/Binaries/systemPostScript interpreters and graphics programs
Graphics/SystemResourcesPostScript definitions and other resources for graphics
Graphics/Packagespackages for setting up graphics

Typical subdirectories of the SystemFiles directory, part one.

Installationvarious auxiliary programs used in installation, called automatically by the main installer program
IncludeFilesfiles for inclusion in other programs
Javafiles for the Java Runtime Environment (if needed)

Typical subdirectories of the SystemFiles directory, part two.

Files of information to be displayed by the Wolfram System Help Viewer are stored in the Documentation directory.

System/Guidespages that categorize and link to related functions
System/ReferencePages/Symbolsreference pages for each of the Wolfram System's built-in objects
System/ReferencePages/Formatsreference pages for file formats that the Wolfram System handles
Packages/name/Guides, etc.documentation for add-on items

Typical subdirectories of the Documentation directory.

Loadable Files

You can customize your Wolfram System by adding files that can be loaded into the system under different circumstances. Such files are conventionally placed in either systemwide or userspecific base directories.

$BaseDirectorysystemwide base directory for files to be loaded by the Wolfram System
$UserBaseDirectoryuser-specific base directory for files to be loaded by the Wolfram System

Base directories for files to be loaded by the Wolfram System.

C:Documents and SettingsAll UsersApplication DataMathematica

Typical values of $BaseDirectory.

C:Documents and SettingsusernameApplication DataMathematica
~ /. MathematicaLinux

Typical values of $UserBaseDirectory.

You can specify different locations for these directories by setting operating system environment variables when you launch the Wolfram System, as discussed in "Wolfram System Sessions".

ApplicationsWolfram Language application packages
Autoloadpackages to be autoloaded on startup
FrontEndfront end initialization files
Kernelkernel initialization files
Licensinglicense management files
SystemFilesgeneral system files

Typical subdirectories of Wolfram System base directories.

Some files in base directories serve as configuration files, automatically used by the Wolfram Language kernel or front end.

Kernel/init.mrun when the kernel is started
Kernel/end.mrun when the kernel is terminated
FrontEnd/init.mread when the front end is started
SystemFiles/FrontEnd/StyleSheets/customized notebook stylesheets
SystemFiles/FrontEnd/Palettes/additional palettes to appear in the front end menu

Some typical kernel and front end configuration files.

Kernel configuration files can contain any Wolfram Language commands. These commands can test global variables such as $SystemID and $MachineName to determine what operations to perform. Front end configuration files can contain only certain special commands, as described in "Input Syntax".

Applications/name/named add-on applications
Autoload/name/add-ons to be loaded automatically when the Wolfram System is started

Subdirectories under $BaseDirectory and $UserBaseDirectory.

With the default setting for the kernel $Path variable, an addon can be loaded from within a Wolfram System session simply by using the command <<name`. This will load the init.m file for the addon, which should in turn be set up to load other necessary files or packages.

By placing an addon under the Autoload subdirectory of $BaseDirectory or $UserBaseDirectory, you can have the Wolfram System automatically load the addon whenever you start the kernel or the front end.

Kernel/init.man initialization file to be loaded by the kernel
FrontEnd/init.man initialization file to be loaded by the front end
Documentation/documentation to be found by the front end

Typical possible contents of the directory for an addon.