Insights

Reflecting on Power and Physics in Technology

By Jen Fraser

A few weeks ago, I attended a coding conference with engineers, developers, programmers, coders, hackers – whatever title is preferred – hosted at Twitter headquarters in San Francisco. The crowd was made up of attendees from the various technology companies in Silicon Valley, everyone representing their company brand with a t-shirt or hoodie. There were four main presentation theatres and topics ranged from “The Future of Data Science” to “Test Automation in DevOps” to “the Internet of Robots.” You could hear the lingo and inside jokes that galvanize this group of individuals who spend more time in front of terminals than other humans, this is not a dig, these are my people.

I had been asked to speak at the event and decided to discuss some of the physics behind operations at technology companies. I have been interested in speaking about “The Physics of Big Data” for some time as physics has largely been minimized as behind-the-scenes “magic” while the product or app is the primary focus of most engineers at technology companies.

I asked the audience to recall how non-visible waves carry the requests from your phone to the router or cell tower where they are then converted with lasers to visible light and travel thousands of miles around the world in fiber to a data center to retrieve the requested image or information off machines. This all occurs nearly instantaneously (literally the speed of light) else we get annoyed and lose interest impatiently. I joked back to the dial up, and emphasized that the actual process is fundamental to the understanding of how the technology has developed over time.

My background is in mechanical engineering with thermodynamics and heat transfer efficiency which led me towards building large scale computing facilities. The chain of heat transfer that moves heat from the surface of the power consuming hardware and rejects the heat into the environment is something I find interesting. The fundamental physics of forced air convection from the surface of a heat exchanger sitting on a CPU and rejection of heat into the air is grounded in the conservation of energy known as the first law of thermodynamics. Warm air from the server returns to air handling equipment where it moves across a coil with water or refrigerant (psychrometrics) methodically moving the heat into the coil to be taken to a compressor or cooling tower to reject the heat to the atmosphere.  I compared people to the machines – 345 BTUh while seated in a theatre or office rejecting latent and sensible loads into the space. Human rejected heat is processed with similar office air conditioning systems to maintain that comfortable office temperature. All of the principles are simple and relatable when broken down to energy.

The majority of engineers don’t think about these processes on a daily basis – but they do care if their product is down! The electrical power systems supporting the data center buildings are sophisticated to avoid power interruption but simple in principle. The power is generally from standard utility sources with chemical storage systems (batteries) or kinetic energy systems (flywheels) to  carry the load during utility interruption while the stationary systems (diesel generators) come online to provide local power generation. This is relatable given the recent power outage downtown San Francisco that interrupted wifi service, traffic and general connected life a few weeks ago.

The intent of this talk was to make the physics behind the technology more approachable.  I had brought with me a small device, it was originally a medical treatment device from around 1910 that delivers electricity to the surface of the skin to stimulate muscles. It's a simple form of electricity generation, in a 6”x6”x14” box, consisting of a coil that rotates with a hand crank, a stationary magnet, and then two copper paddles with wooden handles.  It generates a low voltage, depending on the speed you turn the coil, and releases a charge similar to the feeling you get when you touch an electric fence.

In the past I brought this miniature generator to work during an open house and watched guys  crank the handle while their friend held the copper connections wanting to generate the maximum charge for someone to feel. Often times they would crank it before their friend picks up the paddle, thinking they are building a stored electric charge like would be held in a capacitor, though this device doesn’t have a capacitor. This group was really excited to touch and see the generator and surprised by the simplicity as with most engineers. I asked someone to crank the device while I held the paddles to ensure the charge was working as the the connections sometimes get corroded. I purchased the device at a discount because the antique store said it was “broken”, which meant the copper connection wasn’t conducting and they didn’t understand how it worked.

I’d like to pause for a moment to make a clarification about an assumption you might have made regarding this conference. This is largely a single gender event, yes that’s right, this conference was 90% female, both the speakers and the attendees. The significance of the composition didn’t dawn on me until women started to play with the generator. They were cautious in cranking the generator making sure not to charge it too quickly. These engineers even held hands so the charge would pass through a few people at the same time to experience it together with the person doing the charging rather than inflicting a charge on each other.  

I enjoyed spending my Saturday in the company of female technologists who shared what they knew about their field openly. They were interested and inquisitive about the physics they studied which underlied their current applications. I appreciated the thoughtful way women approached power, with the same fundamental technical comprehension but also with caution and mindfulness about how it impacts others.

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@jenniferfraser

Jen Fraser

‎@jenniferfraser‎

Director, Data Center Engineering, Twitter

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