NoobAlice [1] filed a deletion request for hdup [2]:
Project is gone from project page, author abandoned ( http://www.freehackers.org/Backup#hdup.2C_hdup2.2C_hdup16_and_others ), 404s on download links (per comments, since 2016).
[1] https://aur.archlinux.org/account/NoobAlice/ [2] https://aur.archlinux.org/pkgbase/hdup/
Request #12766 has been accepted by Alad [1].
aur-requests@lists.archlinux.org