Do you currently work with or know anyone who is still using dBase/Clipper/CLARION/Paradox/other DOS RAD environments on period hardware to run business processes? CNC mills/spectrometers/microscopes/other industrial instruments controlled by ISA cards? Anything with a parallel port dongle? If so, I'd be very interested in hearing your experience here.

A certain nuclear power plant had a Windows NT 4.0 machine running as late as 2007. The machine's purpose was to report status of the control rods. The original software was written for Amiga OS. In the mid '90s, the utility purchased an Amiga OS emulator that ran on Windows NT 4.0. The emulator was developed by a firm in the UK that went out of business in the late '90s.

Windows NT 4.0 was the last OS to allow the emulation software direct access to the physical hardware. Later versions of Windows abstracted the hardware access away, and the monitoring software broke. The utility chose to keep the existing hardware and software. Spare hardware was purchased off eBay and stocked on an adjacent shelf.

One commenter noted a factory that had a BBC model B still doing a job around that time. The IT supplier went to a museum to ask if they could buy an exhibit because something had failed locally. The museum gave them the part. These companies have not replaced their computers because to the user there is no separation between the computer and the machine it controls.