Complex sentence: Satriani began the song while it snowed in during a vacation in Lake Tahoe in 1993; it wasn't until 2007 that, upon the urging of his son, ZZ Satriani, he realized it was strong enough to finish.
Split into simpler sentences: Satriani began the song while it snowed in during a vacation in Lake Tahoe in 1993. It wasn't until 2007 that, upon the urging of his son, ZZ Satriani, he realized it was strong enough to finish.