Nand2Tetris Part One

May 12, 2024

I've just finished the first part of the nand2tetris course, the goal of the first part is to explain how computer hardware works.

To achieve that, students implement a simple computer hardware design starting with NAND gates — a chip that takes a pair of 0s and 1s and applies "not and" logical operation, e.g. "1 NAND 1 = 0". Basic NAND gates are used to build other chips like AND, OR, NOT, etc. Next they are used to build an Arithmetic Logic Unit (ALU, a computer's calculator), a Central Processing Unit (CPU, a chip that executes computer programs), and memory chips to hold data and programs — registers and Random Access Memory (RAM). Finally, students put these pieces together to build a computer. Every chip input and output is defined by the task, while students have to figure out their internals.

The interfaces of the basic logic gates and memory chips are self-evident. However the interface of the ALU and the CPU are not. To explain their design, the course introduces an assembly language and its mapping to a binary form. That means the course does not exclusively focus on the hardware part but also on the software. However only on the concepts that are tightly coupled with the hardware implementation.

Essentially, designing a computer is an exercise in building layers of hardware abstractions on top of each other. The course uses Hardware Description Language (HDL) which is a simplified version of the real-life VHDL and Verilog. Emulators are provided to test HDL, assembly, and binary code.

The course is split in 6 projects (12 for both parts 1 and 2). For each project I watched the video first, then read a matching book chapter before doing a unit's task.

In the last project of the first part students need to implement an assembly to binary translator. For this, they may use any programming language they know, and the translator is designed to run on a student's host machine, not on a computer designed in the course (otherwise it must be done with 0s and 1s!). Personally, it was a great excuse to do some C programming after a long break.

The requirement to know a programming language makes the course not accessible for those who haven't touched programming yet. Plus provided instructions assumes familiarity with the basics of Object Oriented Design, very common in academia, but completely not necessary to implement the requested logic. However, for those who don't know how to write programs or aren't interested in taking the second part of the course (focused on software) the completion of the last unit is not necessary. Thus, the first part of nand2tetris could be even studied by school students.

I highly recommend Nand2Tetris part one for Computer Science students, hobbyists and professional programmers. The course will definitely help you to be a better programmer. If you are struggling with pointers in C, or don't get the GNU/Intel Assembly language, completing this course would help you to bridge the gap and finally understand them.

Even non-programmers who are interested in how computers work should give it a try.

Get materials here: nand2tetris.org.