It's not entirely clear to me what the specifics are on how GDC download tokens (for downloading TCGA data) work. Occasionally I'll find that the token I'm using has expired, but have no idea whether they expire after a certain time has elapsed, or automatically when another one has been downloaded by the same use. So I'm wondering:
1) Can one maintain multiple active tokens? 2) Can one copy a token and will each copy still work? 3) What determines if/when a token expires?
Thanks.
Zhenyu Zhang may be able to address this but otherwise you should directly write to GDC help desk for an authoritative answer.