My work runs some scientific instruments on Windows 3.1 and Windows 98 still. The equipment is from the 80s and cannot be upgraded. To buy a new one costs 5 million dollars. Ironically, when parts break on it now, it’s super expensive to fix because of rarity of parts. Luckily the computers are not on the internet.
Dynamic secondary ion mass spectrometers, or D-SIMS for short. It’s an analytical tool to measure very low concentrations of elements in materials. We use it to help mining companies find gold that’s wrapped up in various minerals like pyrite.