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The drum part of 'Rosanna' was developed from John Bonham's playing on 'All Of My Love', speeding up the tempo and adding a bugaloo bass drum figure.:
Jeff Porcaro: Yeah, but the thing is I didn't go out and buy a John Bonham drum book and read the part. There are things, and I know this from my own experience, that you have to have an ear to hear before you can play them. Even if you have the best set of reading chops around, your ears have to be open enough to hear. If you're the kind of drummer that has to see something written before you can feel it, then you should quit school, stop buying books and open your ears to the music. (Hitmen, vol.1, nr.1, 1982)
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""That's pretty funny. You know where that [drum rhythm] came from? Jeff and us were really into Led Zeppelin, and Jeff morphed Foolin the rain (from Zeppelin's In through the out door) and a Bemard Purdie drum groove (from Steely Dan's 'Home at last') and came up with that Rosanna groove. So we went from there - by the end of that afternoon, we had done the basic rhythm track and I'd overdubbed some of the solo. Bang! The end vamp was never supposed to happen, we just started jamming and that's exactly what you hear. We still record that way..." (Steve Lukather, Guitar Techniques, March 2003)

