I am working on a similar project for the Omnibus. I am connecting a Microsemi SmartFusion FPGA to the Omnibus, and doing the peripheral emulation in a combination of the FPGA and Linux running on the ARM Cortex-M3 hard core in the FPGA. Anything with timing restrictions goes in the FPGA. Everything else goes in Linux as a combination of a device driver and an application. For simplicity, I am starting with programmed I/O devices, with the paper tape reader/punch first. I should be able to add serial ports, printer ports, analog I/O, diskettes, card reader, and maybe DECtape. Later I will add data break (DMA) and add disks and mag tape. I am planning to keep the disk images in flash, load them into RAM and run from there, and save them back to flash if the processor is halted. The MI8E bootloader wiggles the same Omnibus signals as the front panel. I could have the FPGA do the same, and load any one of a selection of bootloaders. I am not adding memory, because a nice 32kW RAM board already exists. -- Michael Thompson