This bitmap format is used in the Kodak DC series family of cameras. It is also known under the name Kodak Photogen. KDC is a RAW photo format for the post-processing of photos that has the ability to change key image parameters while maintaining the original level of detail.
This format was used for storing databases on the Pegasus and Palm PDA devices. Besides images, PDB allowed you to store tables, maps, e-books, and other data in a structured way. Today it has become obsolete and has been replaced by more flexible formats with DRM protection.