A method, and tape storage device configured to perform such method, according to various embodiments, includes writing data stored in a buffer onto a tape; writing an interval marker on the tape after the data stored in the buffer is written onto the tape; writing next data subsequent to the interval marker when the next data is stored in the buffer in a first round corresponding to a first-time write in a single track in the tape; writing data stored in the buffer in an area of the interval marker in a second round corresponding to a second-time write in the single track; and writing data stored in the buffer in an area of the interval marker in which no data is written in each of third and subsequent rounds corresponding to third- and subsequent-time writes in the single track.