Windows DDB
From Just Solve the File Format Problem
Windows DDB (Device-Dependent Bitmap), or Windows BMP v1, is a graphics format associated with Microsoft Windows 1.0. It has only a little in common with the BMP formats that succeeded it.
Disambiguation
The term DDB is also used for the in-memory BITMAP structure used by the Windows API. This structure is not necessarily the same as the file format described in this article. (Maybe it is the same on old versions of Windows?)
Format
Files begin with a 10-byte header.