An ink-jet head includes a passage unit including a plurality of pressure chambers each connected with a nozzle and arranged in a matrix in a plane to form a plurality of pressure chamber rows in a first direction in the plane, and a plurality of common ink passages each extending along the first direction and communicating with the pressure chambers. The stator includes a stator core in which a plurality of slots are formed at an inner circumference thereof and stator coils which are fitted into the slots. Based on the comparison, if the user’s access to the storage resources has exceeded the access quota, the storage system can limit access to the user to the storage resources. Exposure to the high power signals may damage the lower-tiered user equipment.