A portable data storage device, e.g., a digital video camcorder (DVC), which stores environment setting data including time data and has an interface which enables a mutual data transmission with an external host computer. Video and audio data are transmitted and received between the DVC and the computer through the interface, and various control data for controlling the DVC and environment setting data are also transmittable from the computer to the DVC. Where the computer transmits the environment setting data to the DVC, the DVC stores the received data in a storage portion. Accordingly, without complicated manipulation of a plurality of keys on the DVC, a user easily inputs data related to the environment setting of the DVC from the computer. Where time data is provided to the DVC from a time standard, accurate current time according to the time standard is recorded on a magnetic tape during recording.