Programming Electronic Music in Pd, Pd was initiated by American software engineer Miller Puckette, who previous co-developed the well known and similarly structured software Max/Msp. Pd is not commercial software; i.e., it was not developed by a corporation and is not for sale. Instead, it is “open source”: its source code is not the (patented) property of a corporation, but is rather freely available to all. One drawback to this is that a detailed operating manual for users who lack programming experience has not exi.