Review: The ARITH-MATIC S1-MU Teaches You How RAM Works

As a reader of the Hackster.io blog, it’s probably safe to assume that you consider yourself to be computer literate. You probably understand that computers use transistors to process data, and that that data is stored as ones and zeroes in binary notation. But do you know how computer hardware actually works at a low-level? Even many tech experts don’t, because modern computers have so many abstraction layers that you don’t need to know what the hardware is actually doing. ARITH-MATIC makes kits designed to teach you how that hardware works through hands-on experimentation, and the Series 1 Memory Unit is the newest kit they have on offer.

The S1-MU is the second kit that ARITH-MATIC has developed, and it fills out the memory slot in the fetch-decode-execute cycle. In conventional computing, the memory unit handles the fetching. The decoding is done by the control unit, which ARITH-MATIC is currently developing a kit for. The arithmetic unit performs the execution, and the S1-AU kit is already available to learn how that works. Put the three units together, and you have the basis for the underlying structure of all modern computers.

Of course, explaining that isn’t enough to help everyone truly understand what’s happening. Many of us are hands-on learners, and need to see the gears turning ourselves in order to fully comprehend how a system works. That’s what ARITH-MATIC’s kits do, and the S1-MU is the kit you need if you want to learn about how computer memory — specifically RAM (Random-Access Memory)— works.

The S1-MU kit comes with everything you need, so you don’t have to worry about purchasing any additional components. Inside the box is the main PCB, a second blank PCB that acts as a protective back plate, and all of the discrete and IC (Integrated Circuit) components you need to assemble your kit. All of those components are through-hole, so putting the PCB together should be easy for anyone with basic soldering skills. The PCBs and all of the components are very well made, and I didn’t run into any difficulty with my kit.

Once your S1-MU kit is assembled, you can follow ARITH-MATIC’s extremely thorough guide to learn how to use the memory unit. The guide provides both practical information on how to operate the S1-MU, as well as the theory behind it. For example, you’ll learn about why bytes are often split into two 4-bit chunks called nibbles. You’ll also learn why registers (temporary storage for those bits) are used, and how they provide a versatile way to move data into and out of RAM chips.

The most enlightening aspect of the S1-MU, however, comes from actually manipulating those bits yourself. Using a set of four buttons and LEDs as inputs, you can send nibbles into two registers. Those can then be used to reference a data location in the RAM chip, and either overwrite that location with new bits or access the bits that are already stored there. This will require a rudimentary knowledge of binary notation, but that’s easy to learn and the labels on the board do a lot to help.

This kit is, quite frankly, a niche product. Its only purpose is to help you learn how bits and are moved into and out of computer memory. But ARITH-MATIC has done an incredible job at making that as intuitive as possible to understand. The £39.95 (~$50) S1-MU kit is high-quality, satisfying to use, and definitely worth the price if you want to gain more knowledge about how computers really work.