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Linux On a Motorola 68000 Solder-less Breadboard
New submitter lars_stefan_axelsson writes: When I was an undergrad in the eighties, "building" a computer meant that you got a bunch of chips and a soldering iron and went to work. The art is still alive today, but instead of a running BASIC interpreter as the ultimate proof of success, today the crowning achievement is getting Linux to run: "What does it take to build a little 68000-based protoboard computer, and get it running Linux? In my case, about three weeks of spare time, plenty of coffee, and a strong dose of stubbornness. After banging my head against the wall with problems ranging from the inductance of pushbutton switches to memory leaks in the C standard library, it finally works! (video)"
Thanks for all the comments! This "68 Katy" is my project. The video is a good overview, and lots more tech details are at http://bigmessowires.com/2014/... and the rest of the site. I've built a couple of other home-made CPU / computer projects in the past, including "Big Mess o' Wires" a few years ago, but this was the first time I tried to add a real OS. Cramming Linux into 512K was a challenge!
The CPU is a 68008, which is a low cost version of the familiar 68000 with an 8-bit bus and fewer external address pins. It has a max of 1 MB of total address space. It’s paired with a 512K 8-bit SRAM, and a 512K Flash ROM (of which 480K is addressable – the remaining 32K is memory-mapped I/O devices). My 68008 runs at 2 MHz (it was unstable when tested at 4 MHz), providing similar performance to a 1 MHz 68000. That’s pretty slow, even in comparison to 68000 systems from the early 1980s, which were typically 8 MHz or faster. So frame rates in the latest games aren't great...