Joshua

engineering leadership

The Elements of Computing Systems

Posted on May 29, 2016

This course is run by some guys from the Hebrew University of Jerusalem. Its about building a computer from nand gates in a hardware simulator, building an assembler, programming language and a kernel from first principles.

So far its been very interesting and informative - I’ve made it through to the third project in about 2 days or so of work. I posted this in their forums as a suggestions, but the only thing that caused a bit of churn for me was trying to remember much about boolean algebra – this is the first principle behind taking a nand gate and progressively building up to an arithmetic logic unit in a CPU. They spend a bit more time of the tools they use (hardware description language, hardware simulator) than they do on deriving the implementation of the chips from the nand gate itself. This didn’t stop me from completing the assignments, since after twisting and turning a bit its not much more than algebra and a few key “ah ha” moments. But, it does potentially stop someone who isn’t familiar with computer science from picking things up, which I think should remain a goal.

One of the surprises, thinking about this, is how effective this teaching method could be for someone who wants to learn from the hardware up. This is not typically the way computer science is taught. All intros that I am aware of, as well as into later stages of learning are more about languages, data structures, algorithms and specifics of technologies (web apps, browsers, html, etc). I really do wish we took a more holistic approach to this learning process.

This is especially prevalent among self-learners, which are more and more common these days in the industry. We tend to ignore the inner workings of the machine in favor of building something tangible (which is not necessarily a bad thing), but then later in your career you may find yourself wanting of knowledge and not necessarily sure about the swiftest path to attaining it. Anyway, this is basically the journey I am on (getting closer to the hardware), though I have spent a ton more time around c, c++, and assembler than your average web app nerd. So far, this class is a nice stepping stone on the path.

One thing that was disappointing, but not totally unexpected, is that they don’t focus so much on the actual hardware implementation of the abstract chips they are building. It would be really nice to have an appendix or optional path that focuses on an overview of the most current forms of these technologies and how they have optimized things over time. They only spend a few moments on these questions (basically a random question from the ‘audience’ at the end of each section). You have to simplify and focus on the end goal if you’re to complete something like this in a matter of weeks. However, its a little frustrating not knowing just how different their ‘ram chip’ is from real world DDR3 RAM that you’d stick in your machine today.

Overall, really good things to say about this course so far, and I’m looking forward to finishing it.