My guess is a combination of spares purchased with the original equipment and maintenance.

This reminds me of that school district that uses an Amiga to control all their scoohls heating and air conditioning. You'd be surprised at how manny old computers you will see in the work place. We're I work we have to keep a 16bit dos system for some old finance solftware witch can't be change. That and the system needs to be able to get online and attach to a networked drive. 😒 I like old computers, but that thing is a pain in the butt.

My pulmonologist still uses a Pentium 75 with his equipment. I chuckled the first time I saw that, I really wanted to offer him something faster so that I could grab that system instead. 🤣
A couple of weeks ago I visited a otorhinolaryngologist to check out why I couldn't breathe properly. I ended up asking him about the IBM PS/2 Model 30 he owned for handling all of his equipment!

Doctors tend to have really old computers for use with their equipment, just because they've become accustomed with a specific software suite that only works in DOS or Win3.1/95 or maybe because the equipment uses specific ISA/PCI cards to communicate with the system. They'd have to do a complete overhaul, so they just postpone it as much as possible. They get special tech support from companies that specialize in this kind of hardware and it ain't cheap. A lot of people here on Vogons would probably kill to be in this business, I know I would, working with retro hardware hehe 🤣 .

Wouldn't be surprised if its embedded not actual PC's.

The article says it was the airport lighting system that still uses 3.x and I can imagine this simply being a simple touch screen or more likely simple control panel somewhere with a few buttons, with windows flashed on a chip, DOM or similar, nothing resembling a PC. probably completely stand alone or at best simple input from another system but no real connectivity to the outside world.

There was a big article few years ago about QANTAS using Windows 3.11 for their inflight entertainment systems.
http://news.bbc.co.uk/1/hi/technology/7707016.stm

Comes down to a balance of "if it aint broke" but at the same time as the article mentions finding people skilled in old tech systems becomes gets harder, therefore more specialised = higher cost.

A lot of technology became to expensive the more out of date it becomes not because of components but because lack of skill in the workplace

chinny22 wrote:

Wouldn't be surprised if its embedded not actual PC's.

Yes.

The previous job that I had for almost 12 years (2001 - 2013) was managing a production environment. We had CNC machines and PLC controlled automated systems and their "PC" parts (sometimes a regular desktop PC with specialized cards installed but mostly something embedded and weird) were booting into all kinds of OS's (DR-DOS, MS-DOS, Windows 3.1 / 9x /2k / XP...)

Ah, industrial computing. Nothing says reliable software like a few thousand lines of VB.

chinny22 wrote:

Wouldn't be surprised if its embedded not actual PC's.
There was a big article few years ago about QANTAS using Windows 3.11 for their inflight entertainment systems.
http://news.bbc.co.uk/1/hi/technology/7707016.stm

With Aerospace in general, you have to add in the fact that everything has to be flight certified (even the infotainment systems), which in and of itself is expensive and a hassle.

The space shuttle flew its last mission with the same AP-101 computers as the first flight, and they use core memory.

Actually:

From Wikipedia...
The AP-101B originally used in the Shuttle had core memory. The AP-101S upgrade in the early 1990s used semiconductor memory.[4]