Comment by blincoln

There are major corporations running key business software which is 30, or even 40 years old. I wouldn't be surprised if some were evening hitting 50+ with old COBOL mainframe applications.

This is one of the main reasons that corporate OS producers like Microsoft support backward compatibility that seems excessive.

You're probably right that within a given hardware platform, older software will generally be very fast on newer hardware, but if one tries to migrate platforms (e.g. mainframe emulation on Linux or Windows), that's not a safe assumption. Around 2009, I saw a team try to migrate some of those early-80s mainframe apps to an emulator, and even on high-end HP servers running Windows, performance was too poor to use a lot of it in production, because it had all been written with ridiculously high-throughput mainframe storage I/O in mind, and emulation couldn't keep up.

You may think (as I do) that those corporations should just bite the bullet and replace those old apps with something modern, but they're the ones writing the checks, so Microsoft and company give them what they want.