I’ll qualify ‘regular usage’ to mean still in daily use, albeit if only by a single person or organization. The usual reason that old tech continues to be used regularly is usually because it still meets some specific need: if it still works, there’s no reason to update or replace it.
I’ve been mentally putting this list together for a while based on articles I’ve come across. It’s not a comprehensive list, and I’m sure there’s far more examples. As someone who likes to tinker with retro computers, I find the fact that people use old tech for legitimate business reasons (and not just for a hobby) particularly interesting. I’ve also added a few links to other related regular activities that revolve around groups interested in using old tech:
- DNA synthesis using 68000 based Macs running Mac OS 7.5
- ICBM missile control systems using 8″ floppy disks
- (up until just a few years back) ATM machines running IBM OS/2
- New York Subway MetroCard fare card machines running IBM OS/2 (Blonde Guy lists on his site that he still provides OS/2 support to New York Subway)
- OS/2 is still sold as commercial product today by eComStation with updated drivers for today’s hardware
- In 2015, a company called Arca Noae announced they had acquired a license from IBM to sell a new distribution of OS/2, with a new version to be released Q3/2016
- Warpstock, the OS/2 conference still runs annually both in the US and in Europe
- The popular virtualization software on the Mac, Parallels, was originally developed to virtualize OS/2 on modern PC hardware so that businesses running OS/2 based systems could continue to run their systems on current day hardware
- A Commodore Amiga is still running the heating and cooling systems for a school district in Grand Rapids, Michigan
- A car auto shop in Poland that’s still running it’s business systems on a Commodore 64
- The article “If it ain’t broke, don’t fix it” on PCWorld lists a number of old computers being used in interesting places, like PDP minicomputers being used for US Navy radar systems and at the UK Atomic Weapons Establishment (there’s no link to sources to confirm if either of these are true, other articles about PDPs being used at either of these only link back to the same article. This article lists 4 known PDP-7s from the 1960s/70s still in existence, but only one is still operational today (as of 2011).