Wikipedia
Dcraw
dcraw is an open-source computer program which is able to read numerous raw image formats, typically produced by high-end digital cameras. dcraw converts these images into the standard PPM and TIFF image formats. This conversion is sometimes referred to as developing a raw image (by analogy with the process of film development) since it renders raw image sensor data (a " digital negative") into a viewable form.
Development began on February 23, 1997. According to the RCS log version 1.0 was released in revision 1.18, on May 5, 2000. Versions up to 3.15 used the name Canon PowerShot Converter, starting with v3.40 the name was Raw Photo Decoder, switching to Raw Photo Decoder "dcraw" in v5.70. Version 8.86 supported 300 cameras.