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I was born in Amsterdam in August 1962.  My elementary school was the Cornelis Vrijschool, and for high school I went to the Amsterdams Lyceum (OLO).  I received my Ph.D. in computer science from the Vrije Universiteit (Amsterdam) in September 1989, under the supervision of Andy Tanenbaum.  I moved to Ithaca in October 1989.  I am now a senior researcher in the Department of Computer Science at Cornell University in Ithaca, NY. For my professional home page, click here. I'm married to Lesley Greene, and have two daughters:  Anneke (born Feb 15, 1996), and Tanya (born July 9, 1997). I've also had two year-long exchange kids, Jeab and Bink. Lesley works for the Kitchen Theatre, and is a terrific dancer and flute and trumpet player. Click here for pictures.

Guitar/Ukulele/Banjo/Lap Steel

I've been playing guitar since about 1987.  I've been playing rhythm guitar for the Ageless Jazz Band since December 1997.  We play many weddings and festivals, and recorded two CDs. I also play banjo with the JazzHappensBand and we recorded a CD as well. I've played in the pit orchestra of high school productions of The Wiz, Annie, Kiss me Kate, Big, Oklahoma, Bye Bye Birdie, Hello Dolly, Seussical, Pippin, and for a SUNY Cortland production of "Little Shop of Horrors" (October 1999), an Ithaca College production of "Chicago - The Musical" (October 2010), and a Ti-Ahwaga Community Players production of "Avenue Q" (June 2013). I play guitar, ukulele, tenor banjo, plectrum banjo, tenor guitar, mandolin, and lap steel guitar.  I'm not terribly good at any of these, but it's my primary hobby and I like doing it.  I wrote a book on what is essentially music theory for the ukulele, and this book called "Understanding Ukulele Chords" is published by Mel Bay.   I taught a workshop at the 2004 Ukulele Hall of Fame Museum Expo, and run regular ukulele jams in Ithaca.

Swing Dance

I've been dancing since 1987.  I joined an Amsterdam rock'n'roll dance team, the Rockaholics.  We performed at many festivals and weddings in the Netherlands, as well as on Ibiza, Spain.  After I moved to Ithaca I founded the Extravadancers.  We performed for several years in Upstate New York, including at the first few Grassroots Festivals in Trumansburg, several Corn Hill Festivals in Rochester, and the Potsdam School for Music and Arts.  Together with Cindy Overstreet I won several dance competitions, including the one at the first Cape May Seashore Swing, and I've judged a few.  I still occasionally perform for benefits together with Cindy and my wife Lesley.  I've taught both Boogie Woogie style dance and aerials in Ithaca, and used to be heavily involved with the Ithaca Swing Dance Network.  I was a D.J. for this organization for some years, but now I'm too busy with other activities.

Dutch Club

I founded the Cornell Dutch Club together with Aswin van den Berg.  Although I'm not very involved at this time, I'm still the advisor to this club, and maintain the mailing list.


I'm an active unicyclist, and like to commute to work on it in spite of the long and steep hill.  I can ride, idle on one foot, ride on one foot, hop onto curbs, ride backwards, and some other tricks.  I also rode 50 miles for an AIDS benefit.  I also rode the NYC Five Boro Bike Ride a couple of times, and Le Tour de l'Île de Montréal. I'm a founding member of the Finger Lakes One Wheelers (FL1W) and the Unicycling Club at Cornell University (UC@CU) and organize weekly practice sessions.


I don't stand in front of a lecture hall very often.  I do have a bunch of students I work with, and I taught an advanced systems course, CS614 in Spring 2003.


I won the first obfuscated C Code contest together with Sjoerd Mullender. That must count for something. Perhaps more impressively, I'm a Fellow of the Association of Computing Machinery.