A data storage device includes a central processing unit (CPU) executing an application and a hardware filter. A method of operation the data storage device may include initializing the hardware filter based on initialization information corresponding to a changed application when the application is changed so that the hardware filter supports the changed application, filtering read data that is output from a second memory based on filtering condition data, outputting the filtered data using the hardware filter that has been initialized, and transmitting the filtered data to a host via a first memory.