Vintage Computer Festival West XI is happening next weekend, August 6-7 at the Computer History Museum in Mountain View, California. I’m belatedly dusting off the hardware for my exhibit and preparing the demos and signage. Anybody have a trade show style backdrop they’d like to lend me? 🙂

I’ll be exhibiting three of my hand-made computer creations, each of which has gone through some modifications for the show:

BMOW 1 – My original custom-made CPU and computer that kicked off this blog and my journey into hobby electronics. BMOW 1 is an 8-bit CPU, implemented with 7400-series TTL discrete logic and a few PALs. Built around this is peripheral hardware for I/O, sound, and video. The end result is a custom creation that’s vaguely similar to an Apple II in its performance and capabilities. And it’s all hand wire-wrapped, with thousands of individual wires.

New for VCF West, I’ve cut a porthole in the bottom of the case and added interior case lighting, to showcase the glorious mess of wires inside. I was nervous I’d break something while removing and replacing all the parts in the case, but BMOW survived and is still running strong.

68 Katy – A 68000-powered single-board Linux system that began life as “Linux on a breadboard”. It’s a super-minimal Linux system containing only a 68K family CPU, 512K ROM, and 512K RAM. I began with a 16 year old Linux distro and hacked it to support this hardware and its tiny memory size. The original version was literally built on a breadboard, though the current version is now a PCB with a serial port for I/O.

During testing for the VCF show, I found that 68 Katy was no longer running reliably. I’d previously overclocked the 8 MHz-rated 68008 CPU to 12 MHz. Restoring an 8 MHz oscillator seemed to fix the problems – for now.

Nibbler – Another custom-made CPU and computer with a 4-bit (nibble) architecture. Designed to be simple to build and easy to understand, Nibbler’s CPU core consists of just 13 discrete 7400-series logic chips – individual counters, registers, buffers, and gates. To complete the machine, it adds a few ROMs and an SRAM, as well as pushbuttons, an audio speaker, and a text display. With a 4-bit CPU and 4K of memory you might think Nibbler couldn’t do anything much more interesting than blink an LED, but it boasts some nice games and demos. Like BMOW 1, it’s all hand wire-wrapped.

Nibbler will see a significant change for the VCF show, time permitting. The original design uses a 4K ROM for storing the program – when you want to run a different program, you need to replace the ROM. I plan to substitute a 16K ROM with a DIP switch to control the highest two address lines, so I can select between four different stored programs without resorting to ROM swapping.

 
Antique and Custom Computers Galore

Beyond the BMOW stuff, the other exhibits planned for VCF West XI look great! They include Eric Schlaepfer’s MonSter 6502, Bill Buzbee’s Magic-1, vintage DEC and Data General systems, IBM mainframes, Amigas, TRS-80s, S-100 hardware, and much more. Check out the full list here.

The show hours are 9:30-6:00 on Saturday the 6th and 9:00-5:30 on Sunday the 7th. Do you plan to attend? Leave a comment below, and I’ll keep an eye out for you!