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.
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
Provenance is the ability to record the history of data and its place of origin. In general, it is the ability to determine the chronology of the ownership, custody or location of any object. The primary purpose of tracing the provenance of an object or entity is often to provide contextual and circumstantial evidence for […] read more
While I can’t get into the background here, I was recently asked to describe the most geeky event in history. Something like this is hard to bound and as I asked those around me I got lots of answers from moment the zero was invented (“without that, you got nothing”) to the first demo of […] read more
You can’t work long in computer science until you have to understand the halting problem. The halting problem is concerned with determining whether a program will finish running or continue to run forever. It has a storied history. In 1936, Alan Turing proved that a general algorithm to solve the halting problem for all possible […] read more
The latest fundamental computer security vulnerability, termed Shellshock, was discovered by a vulnerability researcher Stephane Chazelas (a linux shell expert living in the UK) which allows for arbitrary code execution on linux or mac computers through creating a custom environment variable. If you haven’t already, you need to patch your system(s) and you might be […] read more
During my time on the red team, we continually discussed the role of matched filters in everything from GPS to fire control radars. While I’m having a blast at DARPA where I work in cyber, I wanted to review an old topic and put MATLAB’s phased array toolbox to the test. (Yes, radar friends this […] read more