DocAttachments
Uploaded files (sometimes also known as attachments) are kept in a single directory under the data directory: <data_dir>/files.
This is by convention. In the configuration, the location for uploaded files can be kept anywhere in the host filesystem. But make sure that the web server has write permissions to the directory, so that files can be uploaded there.
To reference a file in this directory from a page, use the syntax: [ [media:filename.ext]]. This will convert into the url http://servername.com/files/filename.ext
Usually, a symlink is placed in the publish directory area, so that the web server can find the files at the specified location.
e.g. /var/www/files would be a symlink to /path/to/data-dir/files
Then, the configuration is set so that 'files_url_base' specifies the leading portion of the URL to use to access this symlink.
Notes [edit section]
This page should have information about uploaded files:
Here is the link syntax used for file attachments in WikiMedia:
[ [Media:file.ext]]