Comment by jasomill

IBM released the PC XT/370[1], built around a pair of 68000s and an 8087 with custom microcode to emulate System/370 instructions, in 1983.

It's not hard to imagine a similar system fabricated around an open or licensed processor core today being well within the budget of a major airline today.

Software emulation would no doubt be less expensive, but there could have been regulatory reasons for building plug-compatible hardware.

[1] https://en.wikipedia.org/wiki/PC-based_IBM_mainframe-compati...