> Windows works with 30 year old code, and somehow managed [...]
I don't think Microsoft has any particularly secret sauce here, they just have a good reason to keep it going and the money to do so. Many other cases the money just isn't there.
And don't under estimate the herculean efforts Microsoft goes through, or eat least used to go through, to keep old programs running. It goes far beyond what I would have ever imagined had I not talked to some of the people involved with it. We're talking having the OS detect specific versions of specific programs (e.g. old versions of Quicken) and hot patching specific APIs with bug-compatible behavior so they don't break with an OS upgrade. Microsoft definitely takes backward compatibility seriously.
I don't think Microsoft has any particularly secret sauce here, they just have a good reason to keep it going and the money to do so. Many other cases the money just isn't there.
And don't under estimate the herculean efforts Microsoft goes through, or eat least used to go through, to keep old programs running. It goes far beyond what I would have ever imagined had I not talked to some of the people involved with it. We're talking having the OS detect specific versions of specific programs (e.g. old versions of Quicken) and hot patching specific APIs with bug-compatible behavior so they don't break with an OS upgrade. Microsoft definitely takes backward compatibility seriously.