I’ve reached an exciting point in the evolution of BMOW. All of the individual bits of technology that I’ve built are now coming together, and rather than a proof-of-concept of keyboard or USB or video functions, I actually have a real computer! I took some time this week to put together a few of those pre-existing technology bits, with the goal of doing something that was actually useful. I now have a computer with a rudimentary BIOS, that can download and run the Apple II machine language monitor program over USB, using BMOW’s VGA display and keyboard for I/O. Holy cow, it practically *is* an Apple II. Here’s the monitor program running, having just performed a disassembly of itself:

I have to say, the very ordinariness of this accomplishment on a “real computer” makes it all the more exciting to me. I showed my wife, and she didn’t even understand what I was trying to demonstrate. It’s a computer running some software, so what? But when I think of the layers of abstractions built on abstractions built on abstractions that it’s taken to get to this point, it makes my head spin. Just a couple weeks ago, I was struggling with the basics of text character generation, and it’s only been six weeks since I couldn’t tell a VSYNC from a V6 and my video signal looked like a train wreck. Before that, of course, was all the time spent monkeying with the keyboard interface and the USB connection. And let’s not forget the CPU itself– those Apple II guys used a nice MOS 6502 CPU, whereas BMOW doesn’t even have a discrete CPU. All the core logic and control functions are built upon a home-designed microarchitecture that’s implemented using a small pile of dirt-simple parts, hand-wired pin-to-pin with 1000+ individual connections.

There’s a delicious irony in the way BMOW seems more and more unremarkable as it behaves more and more like any other computer that people are familiar with.  Yet I’m thrilled to have gotten this far. It’s already well-surpassed my original expectations, and there’s still plenty more fun to be had working on an audio system, adding some persistent storage, and building a case, not to mention all the software (BASIC? Games? A web server?) that begs to be written.