Engineering & Code explores the full stack of modern tech—from bits and transistors to cloud fleets and formal proofs. Here you’ll find clear, rigorous walk-throughs of software design, embedded hardware, security architecture, and the physics that underpins them, always paired with code, schematics, and reasoning you can put to work.
The problem Password reuse is one of the most common security vulnerabilities for individuals and organizations. Common approaches to mitigate password reuse include using a password wallet, writing passwords or hints down, or a simple scheme to translate contextualized information (i.e. a site’s name) into a unique password. Most often, users employ a small set […] read more
Tonight, I was rewiring switches to a more modern set of switches. These days I don’t have time to learn by experience, I have to think my way through this. Without experience, I have to go back to first principles. Funny enough, understanding a four way switch is very similar to understanding digital logic and […] read more
This morning before church, I wrote some code to build a contour plot of schools in New Jersey. The “hot” reddish regions have the best schools and the cooler regions don’t. Tech Stuff: How it’s made This wasn’t that easy. Since I had all the code from my previous post, it should have been very […] read more
I don’t want to read about it, just take me to your super cool interactive map. We are moving to the greater New York City area this summer where Tim joins the leadership team of Colgate-Palmolive. As tempting as it is to spend all our time on Trulia, Estately or Zillow looking at specific houses, […] read more
A common complaint among engineers is that modern computers obscure the details of the complicated math they produce. We cringe when children are exalted as “knowing computers” from a young age. Bill Gosper and Richard Greenblatt had perhaps the maximum benefit to “learn computers”. They didn’t have wolfram alpha or even spreadsheets, they had to […] read more
Lower altitude = higher endurance? At first glance this didn’t make sense to me. Air Force pilots will be the first to tell you that you don’t hug the earth en route to maximize your time on station, it is harder slogging in thicker air. At higher altitudes you have lower air pressure and colder […] read more
Cybersecurity and cryptoanalysis is a field filled with logic puzzles, math and numerical techniques. One of the most interesting technical areas I’ve worked goes by the name of satisfiability modulo theories (SMT) and their associated solvers. This post provides a layman’s introduction to SMT and its applications to computer science and the modern practice of learning […] read more
“Intervention in atmospheric and climatic matters . . . will unfold on a scale difficult to imagine at present. . . . this will merge each nation’s affairs with those of every other, more thoroughly than the threat of a nuclear or any other war would have done.” — J. von Neumann Disclaimer: This is […] read more
In my work at DARPA, I’ve been exposed to hidden Markov models in applications as diverse as temporal pattern recognition such as speech, handwriting, gesture recognition, musical score following, and bioinformatics. My background is in stochastic modeling and optimization, and hidden Markov models are a fascinating intersection between my background and my more recent work […] read more
Why learn assembly? It is painful, and nearly useless to know. But once you understand it, you now know how a computer “works”. It is impossible to understand the hardware/software interface without an knowledge of assembly. In particular, if you are in the computer security field, you have to understand how things really work. These […] read more