It's no secret the levels of effort that Microsoft goes through to maintain software compatibility.
However, it's not as well known that Microsoft's hardware division has a similar passion for compatibility
Back in the early 1990s, Valorie worked on printer drivers for Windows 3.1. Her division was led by Steve Shaiman (another person in the division was a program manager named Gabe Newell)
When Steve was cleaning out his office one day, he found a box in his office, and he checked what was inside it.
It was the very first shipment of Microsoft Mice, newly arrived from the factory in Microsoft Taiwan.
He kept one for himself, gave one to Valorie, and sent the rest to the Microsoft archives. Valorie, in turn gave the mouse to me, since she knew I had a collection of Microsoft mice hung up on my office walls.
Fast forward ten years, it's now 2001. I'm working in the Connected Home Business Unit, which was (at the time) located in the same office area as the Microsoft hardware group.
Just for grins, I showed the device compatibility tester for the hardware division (the entire wall of his office was covered in mice).
So what's the first words out of this guys mouth?
"Hmm. I wonder if this thing works with our current drivers? No reason it shouldn't.."
He removes the mouse from the packaging, plugs it into the serial port of his Windows 2000 machine, and the mouse driver on the machine detected the mouse, and started using it.
So the current Microsoft mouse driver even supports the very first Microsoft mouse ever delivered.
Now THAT'S compatibility.