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re: I worked on MSN, Live, and Bing Search at Microsoft, Ask Me Anything! VIEW POST

FULL DISCUSSION
 

What's the most difficult technical issue/solved problem you have ever faced during your working time?

 

Throughout my career, I've faced challenging problems in many aspects of my work. I tend to seek out that kind of work primarily because a good challenge pushes me to think, learn and improve myself.

About 15 years ago, I designed access control security systems. We needed to test hardware with physical cards and sensors and do a stress test with over 100,000 transactions/sec. Now, we could have simulated it, but that wasn't enough. We needed to test the real hardware. So, we came up with a plan to implement it in our office. We mounted several hardware controllers on a wall and connected multiple card readers, biometric readers/scanners, and sensors to it. Next, we had to swipe cards on those card readers which in turn would trigger a bunch of sensors which would cause a door-lock to unlock for instance. Our hardware was all configured and ready to test.

We went to the junk-yard and got an old windshield wiper motor. Then, we headed to Home Depot to purchase a few pegboards, a regulator for the motor, and tracks.

Next, we attached a variety of card readers to the hardware and mounted them to the wall below the rest of the hardware controllers. Then, we placed the tracks on the walls and attached the pegboard to it with hundreds of cards stuck to the board facing the wall (towards the card readers). We connected the windshield wiper motor & regulator to the pegboard in a way that when the wiper was turned on the pegboard would slide back and forth sort of like how the wiper goes back and forth.

What's interesting is how windshield wiper motors work. The motor rotates, but the way the arm is attached causes it to go back and forth. We used this motion to slide the pegboard back and forth on the tracks against the wall. This resulted in cards being swiped on the card readers and various sensors getting triggered. We managed to get about a 150,000 real transactions/sec and I was able to test my enterprise-grade server with the actual pipeline.

I definitely have more stories, but I'll leave those for another time. :)

 
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