A symbol file contains the same debugging information that an executable file would contain. However, the information is stored in a file with a .DBG extension, rather than the executable file. Therefore, you can install only the symbol files you will need during debugging. This reduces the file size of the executable, saving load time and disk storage.
To create a .DBG file, build your executable file with debug information, then use the SplitSymbols function or the Rebase tool.
The operating system dynamic-link libraries (DLL) have associated symbol files. These files are not installed during installation. To install the system symbol files, create a directory on your hard disk, and copy the files from your system installation compact disc (CD). The symbol files are located in the SUPPORT\DEBUG\I386\SYMBOLS directory tree.