#vcfwxiii

I first saw the prototype versions on display at VCF West XIII back in August.  These come from Chris Davis, the same mind who created the Altair-Duino.  I can get it to count, which means I assembled it right.  It looks pretty close to the authentic Kenbak-1 I saw back at VCF East XI in 2016 being operated by John Blankenbaker himself.  I need to find a manual to put this thing through its paces.

Thank you Eric for working with me to create the quick fix that made this Frankensteinian abomination possible.  And a thank you to Lenore and Windell of Evil Mad Scientist Laboratories @evilmadlinks for putting up with my goofiness.  This was a fun experiment that I consider the highlight of VCF West for me.

I exhibited the Cactus at VCF West on August 4th & 5th in Mountain View California, at the Computer History Museum. A few weeks prior to the show, I discovered that the MOnSter 6502   would be in attendance, along with the good folks at Evil Mad Scientist Laboratories.   I reached out to its creator, Eric Schlaepfer, and asked if he would be willing to combine our two machines in an experiment. He was interested, letting me know that as long as I adhered to the NMOS specification and clocked down to 50KHz, the two should be able to work together.   Normally, the Cactus relies on the 65C02's Bus Enable pin to halt the CPU and allow the front panel logic to take over to provide the user with direct memory access. I built a new processor card with additional buffers to account for the lack of such a pin on the NMOS variant, and tested it with an original Commodore 6502 from 1983.   Once at VCF West, our first attempt on Saturday pointed out that I had neglected to buffer the Read/Write line, resulting in bus contention.   On Sunday, Eric brought me a breadboard, some additional jumper wires, and a few tristate buffers from his stockpile.   After splicing an additional 74LS245 into the NMOS card, and testing with an NMOS 6502, we decided to try again.   Lo and behold, the Cactus and the MOnSter 6502 successfully booted into BASIC, and ran at 50KHz for about half an hour, creating a spectacular fusion of blinkenlights.   That makes the Cactus the third machine to use the MOnSter 6502, and the first one that wasn't made by Eric. Needless to say, this was the highlight of my weekend.  

It was nice to see him at VCF West XIII.  He was kind enough to take a picture with me and my masterpiece.

I will be giving a talk & demonstration at the DEFCON 26 HHV at 4PM on August 11th, in Las Vegas Nevada at Caesers Palace .  Come learn about the Cactus, the machines that influenced it, and the build process.  Attendees will be free to try the machine for themselves after the formal talk.

That’s like...  5 I’ve seen in person.

I walked away with some interesting souvenirs too.  The entire year of Byte Magazine from 1977 is a good start, but very heavy.  I was handed a schematic and board layout from the OSI-300, which is basically poster sized.  Plus, I’ve got a pair of punch cards and a printout from the IBM 1401 computer.  Lastly, I have a second place award for best demonstration at VCF West -- I’m honored that they even thought of me.

It’s beautiful… the DEC PDP-1 is beyond spectacular.