I have an Intel 286 @ 8MHz still running. Single disk drive (About 500mb I think).



Single Hard Drive, no backups, single power supply, zero redundancy running Mentor PC/OS (A Pick operating system with a multivalue database).



It's for another business in our family. Around 10 years ago I freaked out that it was still running and the tape drive was old. At that time the company that developed the application had gone out of business (I think even a couple of the developers had died)... The application was current in the late 70s / early 80s. One weekend finally read up enough on how to access the mv tables and explode it into SQL tables and import it to a modern billing system.



Now it's just running to see how long it will last. Had a scare about two years ago. Power went out (this is on C power.. no ups, no generator, etc) and I thought it was done for. Turns out the battery on motherboard was dead and the motherboard required you to manually set hard drive parameters, once I fixed that it booted back up.