Abstract: A memory system comprises a communication interface for transmitting commands and data to a host and receiving commands and data from the host. A storage medium has a first region for storing user data and a second region storing a plurality of first programs. Each first program sets parameters of a signal transmission process to be performed using the communication interface. Each first program has at least one different parameter from the other first programs in the plurality. A controller selects and executes a first program from the plurality of first programs according to a result of a first communication attempt between the communication interface and the host.