Data processing device and motherboard module thereof

A data processing device comprising

• a casing comprising an assembling opening and a cover to mantle the assembling opening;
• at least one connector;
• a first daughter board disposed in and fixed to the casing, wherein the first daughter board has an opening and the connector is disposed on a region of the first daughter board, wherein the region is direct connected to a side of the opening;
• a second daughter board disposed on the casing and electrically connected to the first daughter board through the at least one connector, wherein the second daughter board is identical to the opening in size;
• wherein the location of the second daughter board corresponds to the assembling opening to remove the second daughter board from the assembling opening;
• a data processing component disposed on the second daughter board to process data and programs;
• a data storing component disposed on the second daughter board to store data and programs;
• and
• an input/output interface port disposed on the first daughter board to connect peripheral devices of the data processing device.