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Joining Facebook!

Exploring - Mon, 03/05/2010 - 9:00pm

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.


Exploring - Tue, 02/02/2010 - 2:15am

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!

Recipe: Double Chocolate Chip Peppermint Cookies

Exploring - Sat, 11/07/2009 - 1:43am

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


Laptop + Multiple Monitors Help

Exploring - Wed, 14/01/2009 - 7:26pm

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

Amazon's CloudFront CDN: disappointing

Exploring - Tue, 18/11/2008 - 5:46pm

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.

More human computation with GWAP

Exploring - Wed, 14/05/2008 - 6:08am

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.

Wanted: Temporary Palo Alto Housing

Exploring - Wed, 02/04/2008 - 1:54am

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.

The Open Source Google Stack

Exploring - Wed, 26/03/2008 - 7:40pm

The open source community is slowly growing a software stack that emulates a number of internal Google technologies. What's interesting is that the stack is being developed by a number of tech companies -- ranging from giants (mostly Yahoo!) to medium size firms (Facebook) to startup companies (, PowerSet, Krugle, Veoh). So far, the following pieces of infrastructure have been developed

Silicon Mechanics

Exploring - Mon, 18/02/2008 - 4:05pm

I'm looking at Silicon Mechanics for potentially buying a few rack mount servers. I'm wondering if anybody has good (or bad) experience dealing with them.

On paper, it looks like they have prices that are much cheaper than Dell (of course). Also, they have a nice thing where they can have two servers in a 1U (16 cores in a 1U... that's alot). I just want to see if anybody here has some real experience with them.

Windows Error Messages

Exploring - Wed, 06/02/2008 - 3:18pm

While being out of disk space on a server isn't generally much fun, this error message made it worth the while

Randall Munroe (xkcd author) comes to CMU

Exploring - Sat, 10/11/2007 - 10:00pm

Randall Munroe came to CMU to give a talk yesterday. It was the most attended talk of the semester. Randall's talk was fantastic -- he said that he is trying to fill part of his bedroom with plastic balls (like in one of his cartoons). He also drew two mini-cartoons while talking, which was very cool. Finally, he set two very useful standards. First, he declared that punctuation need not go inside quotation mark (eg, did she say "I love you"?). Second, he declared himself president of the Internet (so that another evil person wouldn't take it.

New reCAPTCHA APIs: i18n and Theming

Exploring - Thu, 08/11/2007 - 7:10pm
We're really proud to announce the release of two new APIs for the client side.

Internationalization For users of our default theme, we've added a way to request the display of the user interface in a different language. We've translated our UI and help page into the following languages


We're looking into getting translations for other languages. If your language isn't supported, you can use the theming API to allow you to customize the user interface.

Updating Ubuntu -- please make it faster

Exploring - Fri, 19/10/2007 - 12:10am

Dear Ubuntu hackers,

Gusty is out. I want it. But the update process for your wonderful operating system is broken. It seems that this process on getting files from a central machine. Said machines seem to be overwhelmed by other users who also want to upgrade -- they won't even respond to a TCP SYN packet

In the future, it'd be really nice if this process used mirrors so that it wouldn't be as flooded.

XKCD teaches SQL Injection

Exploring - Wed, 10/10/2007 - 4:45am
The hacker inside me found this funny

Randy Pausch: an inspiring video

Exploring - Fri, 21/09/2007 - 11:56pm
Randy Pausch is a professor at Carnegie Mellon who believes in making programming, specifically for entertainment purposes, accessible to everybody. Sadly, Professor Pausch has an untreatable form of cancer which will take his life in the next few months. This week, he gave a talk which is truly inspirational. This is a person I wish I could have gotten to know.

M-x gdb

Exploring - Fri, 21/09/2007 - 3:34pm
I really wish somebody had told me about this a long time ago:

Firefox Caching

Exploring - Tue, 04/09/2007 - 8:29pm

Federico posted about some work he was doing on making Firefox not cache as many uncompressed bitmaps in memory. I was playing around with the cache stuff and noticed something: my Firefox cache is full of youtube videos. YouTube videos aren't exactly the best thing for Firefox to cache. My internet connection is fast enough that streaming the videos works just fine.

Yay Dual Homing!

Exploring - Thu, 30/08/2007 - 11:53pm

Today, we had our first drill with dual homing on reCAPTCHA. In Pittsburgh, the water main that serves the Carnegie Mellon area broke today, causing a complete water outage on campus. This has resulted in many servers being shut down. reCAPTCHAs servers were kept up, as they are production servers, however we were told that it was possible they'd be shut down.

Facebook 2.0

Exploring - Tue, 28/08/2007 - 7:42pm

So if your profile says you are single, and looking for women, single women looking for men might soon get a higher ranking in search results? I'm not sure what other "intentions" facebook might know about

Making bugs... and fixing them

Exploring - Tue, 17/07/2007 - 5:13am

Two interesting bugs from today.

First, you gotta be careful with order of operations. I wrote this code:

Yahoo's and Microsoft's CAPTCHAs likely NOT broken

Exploring - Tue, 10/07/2007 - 11:39pm

BitDefender went a bit overboard in their claim about CAPTCHAs. Their statement about CAPTCHAs was issued as a press release (which clearly has meet their goals of getting press -- regardless of the accuracy of their statements). The article states that about 500 accounts are being created per hour. This is about the effort of one person solving CAPTCHAs. If they had actually broken the CAPTCHAs of Hotmail and Yahoo, there would be tens of thousands of accounts every hour.

Life at Google

Exploring - Wed, 27/06/2007 - 6:42pm

This blog is pretty funny. It's sort of like what the Daily Show might say about Google -- the facts are mostly true (some are pretty out-dated), but they're twisted in the opposite direction of how things actually are.

NYTimes Article on CAPTCHAs

Exploring - Mon, 11/06/2007 - 8:08am
The New York Times is running an article today on CAPTCHAs. The article really misses some key points. For example, it talks about the CAPTCHAs on YouTube. YouTube's CAPTCHA is really, really bad. The CAPTCHA is mis-designed, using different colors to attempt to provide security. I can't imagine solving this as a color blind user, it must be nearly impossible. Most CAPTCHA providers have migrated to using a monochrome CAPTCHA (for example Google, Yahoo and MSN).

reCAPTCHA: A new way to fight spam

Exploring - Wed, 23/05/2007 - 4:31pm

You've probably seen a CAPTCHA before. It's those funky letters you have to enter before you sign up for an account on almost any website. I'm proud to announce a new type of CAPTCHA: reCAPTCHA: (click to see a live demo!).

LD_LIBRARY_PATH empty entries

Exploring - Mon, 14/05/2007 - 3:30pm

Many of us developers have a bashrc that has lines like:


I've always known that this isn't perfect, that one should check $LD_LIBRARY_PATH isn't empty, but had always thought it was just a minor point. It turns out that the loader sees an empty entry as meaning the current working directory. This means that it looks there for libraries.


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