This is totally a function of the Tape drive. However, we highly recommend that you use a no-rewind type of device with Data Protector. THere is a HPUX kernel parameter 'st_san_safe=1' that only allows no-rewind devices to he used, but, I am not sure how this would be set on Windows
This means 'no-rewind to the beginning of the tape'. If your media is being appended to, the media will rewind to the last physical 'End-of-File' mark on the tape, then move forward some tape blocks to prevent over-writing something previously written.
But, again, this is not a function of Data Protector