Monday, May 03, 2010

Joining Facebook!

I'm really excited to announce that I'm going to be joining Facebook to work on the infrastructure team. With all the growth Facebook has seen comes unique challenges in scaling systems. I'm looking forward to working on this.

Of course, this also means saying good bye to Google and reCAPTCHA. It's been over 3 years since we started working on the crazy idea of getting millions of people to digitize the world's books in their spare time. I'm looking forward to seeing reCAPTCHA continue to grow.

Monday, February 01, 2010


From time to time, reCAPTCHA will give users odd juxtapositions of words. I got quite a kick out of seeing this one:

I think this would make a great show!

Friday, July 10, 2009

Recipe: Double Chocolate Chip Peppermint Cookies

This cookie is a nice variation on the classic double chocolate chip.

  • 1/2 cup butter (one stick)
  • 1/2 cup brown sugar
  • 1/2 cup white sugar
  • 1 egg
  • 1/4 tsp vanilla
  • 1/4 tsp peppermint
  • 1 cup flower
  • 1/4 cpu unsweatened cocoa powder
  • 1/2 tsp baking soda
  • 1/4 tsp salt


  1. Preheat oven to 350F
  2. Soften butter and mix with eggs, sugar, peppermint and vanilla
  3. Mix flower, salt, baking soda, and cocoa in a separate bowl
  4. Beat in the dry ingredients
  5. Form balls on a cookie tray and bake for 8-10 minutes. Underbake slightly so the cookies are chewy

Tip: I've found that I'll eat these cookies far quicker than I really should. In order to ration the cookies, I will mix up a double batch, and freeze the balls of dough. Once the dough is frozen, you can place the balls in a ziplock bag. The cookies can be baked from frozen by adding 2 minutes to the baking time and last a few weeks. Cookies can then be baked in small batches. I can't tell any difference between cookies from frozen dough or fresh dough.

Wednesday, January 14, 2009

Laptop + Multiple Monitors Help

I'm trying to get my laptop to display on dual external monitors. I'd appreciate some guidance in getting this configuration set up

What I have

  • A Dell Latitude D620 with nVidia Corporation G72M [Quadro NVS 110M/GeForce Go 7300]
  • A Dell docking station with dual-link DVI output
  • 2 Dell 2007FP Monitors
  • Ubuntu 8.04

What I want

  • When I dock my laptop, the two external monitors are used (I don't really need to use the internal screen as a third monitor)
  • When my laptop is undocked, my internal screen activates.

Tuesday, November 18, 2008

Amazon's CloudFront CDN: disappointing

I took a look at CloudFront today. They have really good intentions. The CDN space is quite a mess -- it could easily be a pay-as-you-go, self-service industry. However, players such as Akamai try to make a large profit. The CDN space is especially hard for small sites -- you can't get any reasonable pricing unless you are doing high levels of traffic.

Amazon wants to change all of that. However, I think they made a number of missteps in their initial offering.

  • They aren't using it on They use Level(3)'s CDN! Why should anybody consider using a service Amazon isn't using themselves. This is a chance to prove your CDN in real life.
  • Tiered pricing. In a self-service model, it doesn't make sense to offer different prices for different bandwidth usages. One customer with 100 TB of traffic is the same as 10 customers with 10 TB of traffic.
  • Pay per request. For S3, this made sense. Every request was one disk seek on the servers, and people need to pay for that. However, in a CDN, you are expected to serve from memory. The 1 cent per 10,000 requests effectively adds 6 KB of data to every file. So if you serve a 1 KB file, this increases your cost by 6x. At the very least, the fixed cost per request should be less than that with s3 to account for the lack of disk seeks
  • Lack of peering. Doing a traceroute to cloudfront from a few locations (Carnegie Mellon, colos in New York and LA), it appeared that all of my traffic was going over transit links. In contrast, traffic to went over fast and cheap peering links.

I do hope that Amazon fixes up CloudFront. It's a fantastic concept. They have the power to force reason into the market.

Wednesday, May 14, 2008

More human computation with GWAP

It's oh so exciting to see that GWAP (games with a purpose) has launched. GWAP is part of the research on human computation that started the reCAPTCHA project. GWAP is a framework which allows researchers to create fun games which generate useful data. For example, "Matchin" is a game where you and a random stranger on the internet get a pair of images. You must agree on which one is "better" without talking with each other. The game is fast, fun, and very addicting. From this game, you can actually get quite a bit of useful information. Most importantly, it's possible to find the "good" photos from a site like Flicker.

What I find most exciting about GWAP is that it is a production service. Many researchers will write papers about ideas, maybe create a prototype or a mock-up. However, they don't really do anything to bring their ideas to fruition. Luis's work is different. For example, with reCAPTCHA, we've spent months developing systems for serving CAPTCHAs to the internet. Most of this time was spent making our code reliable, scalable, and fast. Our efforts really payed off. reCAPTCHA now serves CAPTCHAs on a wide range of sites including Ticketmaster, Facebook, StumbleUpon, Twitter and Bebo.

I think this tendency for productionizing is going to pay off with GWAP. Lots of time was spent on things like UI design and scalability. The UI makes the games fun to play, the scalability makes sure that the team can have a real world impact.

Congrats to Mike and the rest of the GWAP team on a job well done.

Tuesday, April 01, 2008

Wanted: Temporary Palo Alto Housing

I'm looking for 1 bedroom in area below between May 1 and Aug 20 (so hopefully, something furnished). Closer to the green arrow thingy is better. Please email me at if you have something like this.