Network IV Rebooted
The original Network IV at the Seattle-Tacoma Airport no longer exists, it was decommissioned in the early 2000’s. The program and design documentation allowed it to be virtually recreated as a means of conserving the work.
Original Network IV program running in SIMH Data General Nova emulation
Andrew Seawright with help from Charlie Keagle
Network IV Rebooted System
The nova SIMH emulator runs on a Raspberry Pi 4B computer. The SIMH nova is loaded with the original Network IV data image extracted from the paper tape. The display is controlled from a Teensy 4.0 microcontroller. The analogue sound is emulated digitally and button inputs are sampled from another Teensy 4.0.
The SIMH nova code was modified to support Network IV IO device 76 (octal) which was a “GPIO” device peripheral added to the Nova 1210 computer to control the sculpture. The device 76 IO channels A, B, and C controlled the lights, sounds, and input sampling in the original sculpture. In the emulation, using SIMH, I/O to device 76 is processed and redirected as commands to the Teensy devices. For example, illuminating a particular lamp, clearing all the lights, reading the inputs, triggering a sound resonator, or changing the pitch or envelope of an instrument. The audio emulation models the three Network IV instruments and the 32 resonators.
Annotated program listing - Data General Nova Assembly Code
Engineering documentation
Reading the Network IV paper tape data
Original Network IV paper tapes