Design rule for Camera File system: Did you ever wonder why the images directory on digital cameras is always named “DCIM.” I sure did, so I finally looked it up today.
Design rule for Camera File system (DCF) is a JEITA specification (number CP-3461) which defines a file format and file system for digital cameras, including the directory structure, file naming method, character set, file format, and metadata format. It is currently the de facto industry standard for digital still cameras. The file format of DCF is based on the Exif 2.2 specification.
[…] The root directory in a digital camera contains a DCIM (Digital Camera Images) directory which contains possibly multiple subdirectories with names such as “123ABCDE”, which consist of a unique directory number (in the range 100…999) and five alphanumeric characters, which may be freely chosen and often refer to a camera maker.