On most of the integrated IMU chips there are only singular seperated sensors:

the Gyro can calculate only 3D rotational speed,

the Accerlerometer can calculate only 3D acceleration,

the Compass can calculate only 3D heading direction.

Most of all IMUs are only providing these three primary output values 3D rotational speed, 3D acceleration, and 3D heading direction, mostly they are cleaned of sensor noise (Gaussian and non-Gaussian noise like sensor drift) by sensor fusioning and filtering by stochastical Filters (e.g., Kalman) - but they still are three seperated 3D values (3*3D = 9D vector)

Digital Motion Processing means, that out of these primary values all secondary navigation values are calculated by an embedded MCU, so you can directly poll

current 3D position (x, y, z) in space (related to a start point),

current 3D speed in space (^x, ^y, ^z )

current 3D spatial orientation (roll, pitch, yaw)

this is what the MPU-6050 / MPU-9150 are supposed to provide.