9915A in a blinking decorative lights display

Yes, I saw it when you posted a message about it to MoHPC. A few years back I ran my Newtonsday [1] lights from a PERQ PERQlink port. Just buffered the data output lines and fed them to LEDs. A bit of pascal to produce the patterns and a bit of microcode to write values to the port completed the project. Somewhat more recently I wrote a Datafile (HPCC club magazine) article of HP calculator controled Nwetonsday lights, using either an HP41 + HPIL + GPIO interface or an HP48 + ARD's I2C interface. HPCC can probably provide copies of that article for anyone who's mad enough to want to try it. I also know of somebody who patched RT11 to write the idle lights display not to the switch register address but to the address of a 'spare' DR11 card. The output of that was buffered and used to flash 16 LEDs aranged in sone tinsel around the top of the rack. [1] As an agnostic I see no particular reason to celebrate Christmas. As a physicist I see a good reason to celebrate the birthday of Sir Isaac Newton. He was born 25/12/1642 -tony