Zuckerberg began using computers and writing software in middle school. His father taught him Atari BASIC Programming in the 1990s, and later hired software developer David Newman to tutor him privately. Zuckerberg took a graduate course in the subject at Mercy College near his home while still in high school. In one program, since his father's dental practice was operated from their home, he built a software program he called "ZuckNet" that allowed all the computers between the house and dental office to communicate with each other. It is considered a "primitive" version of AOL's Instant Messenger, which came out the following year.