Question:
Is one allowed to delete a shiur from one's ipod?
Answer:
Yes, because it isn’t written, but it is only a digital code.
Sources:
Shulchan Shlomo Shabbos 340 ftnt. 17, Avnei Yoshpe Y:D 105, Chut Shani Mezuzah pg. 408, Horav Y. Cahen shlit”a