From NAND to Tetris in 12 StepsI watched another really great video lecture. It's called 'From Nand to Tetris - Building a Modern Computer From First Principles'.

At first I thought it was just a video lecture by some computer hobbyist, but it turned out to be a lecture about a new computer science course for both undergraduate and graduate students, developed by professor Shimon Schocken. The goal of this course is to teach students various levels of abstractions in computing by letting them build a computer from scratch and have it run a computer game.

One of Shimon Schocken's colleagues says that, "Computer science is a thousand layers of abstraction", which is quite true. If we write a program in a high level language, it gets translated into assembly language which in turn gets translated into machine code, which in turn gets executed on hardware platform, which in turn uses logic gates to perform computation which is itself electrical engineering and physics.

This video lecture briefly explains all of these abstractions (except physics).

Before you watch the lecture (it's 1 hour long), you might first want to view a 10 minute introduction, to see if you're interested in this topic:

And here is the whole 1 hour lecture:

Moments from the lecture:

  • [06:55] Course is a mishmash from all computer science topics - hardware, architecture, data structures and algorithms, programming languages, compilers and software engineering.
  • [07:46] Students learn both software and hardware.
  • [10:05] Hardware part uses HDL (Hardware Description Language), a special HDL testing language and a hardware simulator.
  • [10:58] Building elementary logic gates in HDL.
  • [15:30] 16 bit adder, full adder, half adder.
  • [19:32] Building combinatorial gates (ALU).
  • [22:58] Building sequential chips (memory).
  • [23:40] Implementing machine language.
  • [26:30] Building the CPU.
  • [27:48] Building a Harvard architecture computer.
  • [29:58] Input/Output devices. Screen and keyboard memory maps.
  • [30:28] CPU Emulator demo.
  • [33:55] Summary of 30 different chips built in HDL.
  • [34:15] Example of ALU HDL project given to students, including HDL program, test file and a compare file
  • [35:32] Software part starts with writing an assembler.
  • [37:24] Implementing a VM (Virtual Machine).
  • [39:31] VM language.
  • [40:33] VM Emulator demo.
  • [42:30] Writing a compiler for "Jack" programming language.
  • [43:06] Demo of a Space Invaders game, written in Jack.
  • [47:02] Jack code gets parsed into XML and later translated into assembly code.
  • [51:33] Building the OS (Operating System).
  • [53:43] Summary of both hardware and software parts.
  • [57:45] Q and A!

Great news about the course this lecture talks about is that you can actually take it on your own, if you buy Mr. Shimon's book The Elements of Computing Systems. The book covers all the 12 steps in building the computer.

Shimon makes the necessary software, such as HDL, the testing suite and other programs available on book's website.

The course goes under a few different titles, such as 'Digital System Construction', 'Elements of Computing Systems', and the same 'From Nand to Tetris', depending on university.

Apart from that, Professor Shimon Schocken mentioned a few famous computer scientists during his talk. I got interested, and wrote them down for your convenience:

Have fun getting smarter with each lecture and until next time.