8-bit Makes a Better Programmer

In the realm of modern programming, with its high-level languages and sophisticated development environments, the art of programming an 8-bit microcomputer might seem like a quaint, if not obsolete, pursuit. However, diving into the world of assembly language programming on such a system isn’t just a nostalgic trip down memory lane; it’s a journey that offers invaluable insights and a deeper appreciation for the inner workings of computers.

Modern software development would be almost unrecognizable to the microcomputer programmer of forty years ago. At a basic level, the languages and concepts wouldn’t be too foreign: we still write if statements and for loops, and object-oriented programming was already in vogue by 1984. But modern applications are internet-centric, use GUIs and 3D graphics, rely on distributed version control and CI/CD to get built, depend on various runtimes and interpreters, and above all, sit so high in an immensely complex hierarchy of abstractions that it’s as if they are coded for an entirely different architecture of machine than the hardware they are ultimately running on.

Teaching university courses in digital logic design, computer architecture, and system programming to an increasingly younger audience, and now working in the realm of high-level web-native software with developers born into a broadband world, I’ve watched a generation disconnect from the humble ground and float into the cloud from where it can no longer be seen.

Imagine a world where you need to communicate directly with the hardware, where each instruction you write has a tangible, immediate impact on the machine. That’s the world I grew up in. In the 8-bit world, there are no high-level APIs, no advanced frameworks or libraries. It’s just you and the machine. Assembly language is more or less the computer’s native tongue.

This close-to-the-metal programming is more than just an exercise in retro computing. It’s an illuminating experience that sheds light on the foundational aspects of computing. In modern programming environments, layers upon layers of abstraction shield the programmer from the complexities of the machine. While these abstractions are powerful tools that enable the development of complex software, they also distance the programmer from understanding what’s really happening underneath the hood. When you program an 8-bit system, you’re forced to confront the realities of the machine: memory management, CPU cycles, and the limitations of a simpler processor. This confrontation is not merely educational but transformative. It can hone a programmer’s ability to think critically and efficiently. You learn to appreciate every byte of memory and every processor cycle. This level of engagement with the hardware cultivates a mindset that’s keenly aware of the cost of computational resources, an awareness that is often lost in the abstraction-laden world of modern software development.

Moreover, it underlines the importance of systems engineering. Separating concerns into layers with well-defined interfaces is, of course, good practice, but sometimes breaking these boundaries and designing across multiple layers can yield a far more optimal result (take it from John Carmack if not from me). Working with a limited system creates an acute awareness of how each component interacts with others and how decisions at one level can have ripple effects throughout the entire system. This holistic understanding is crucial for any programmer or engineer aiming to create efficient, effective, and robust software solutions.

The stark contrast between the simplicity of an 8-bit computer and the complexity of modern systems also provides a unique perspective on the evolution of technology. It’s a reminder of how far we’ve come and how the principles of computing are still rooted in these fundamental concepts. Understanding why things developed the way they did, historically, is the antidote to a sort of “cargo cult” mentality, where the current menagerie of software components we build on are taken for granted and never really probed or questioned.

My personal quest is the construction and exploration of the RC2014, a modern Z80-based computer architecture quite similar to various popular machines of the late 1970s and early 1980s. To date, I’ve built a basic machine (with separate CPU, RAM, ROM, clock, serial, and storage modules) that runs CP/M, and populated it with a variety of applications, some of my own design. I’ve attached an ESP8266-based wifi “modem” that allows me to dial into telnet BBSes like ConstructiveChaos. I’ve added graphics, sound, and controller interface modules, to the point where I’m able to load and play ColecoVision games. My most recent project is a RAM module and supporting software to allow large games to be loaded into memory via bank switching.

If you’re looking to deepen your understanding of the machine and cultivate a more holistic approach to software development, I can’t recommend a similar exercise highly enough.