Every time we explore the educational side of computing, we discover extremely complex projects that demanded years of effort. For example, it’s impossible to forget the Mega-Processor, a hand-made processor that takes up an entire living room, or the MOnSter 6502, a large-scale reproduction of the classic 6502. But today we came across MERCIA by Jeroen Brinkman, in which there is not a single chip. Everything depends on passive components, and it has some portability, occupying five suitcases.
The Challenge of Understanding Computers
A fundamental problem when teaching how a computer works is that current systems (PCs, smartphones, consoles, etc.) behave like “black boxes”: you can see the input and the output, but not what happens in between. That’s where projects like the paper processor or the marble computer come in. Ones and zeros, changes and transfers, a request transformed into results… or errors, because sometimes things fail.
The Story of MERCIA
However, out there, there are engineers and experts who decide to tackle this challenge on a much larger scale. That brings us to Jeroen Brinkman’s website and his MERCIA project. For more than four decades, Jeroen had the desire to build a computer, but a visit to the Bletchley Park museum and the reconstruction of EDSAC finally convinced him. In June 2014, MERCIA took its first steps, and it hasn’t stopped since.
Design Principles: A White Box on the Move
MERCIA respects several design parameters. First, it has to be a “white box”, showing the user every bit of memory, and for one kilobyte, that requires 27,500 components. Then, it needs a certain level of portability, and for that Jeroen uses suitcases. The ALU, registers, decoder, microcode, RAM, and ROM occupy a total of 4.5 suitcases, and all he has to do is close them. Finally, the design of MERCIA has been standardized, with documentation available. As if that weren’t enough, MERCIA is not based on integrated circuits, nor valves, nor transistors. In other words, it’s a paradise (or nightmare) of relays, capacitors, diodes, wires, and switches.
The goal of MERCIA is that everyone can understand how it works, and there’s probably nothing better than relays for that, even if it needs a gigantic number of components. The official page is full of technical data, but at the same time, we’d love to see more videos about MERCIA in the future.
Official site: Click here
Source: Hackaday
