This blog is going to be mainly programming orientated with a dash of oldschool. Major shout out to Raymond Chen who knows full well the pain of backcompat.
At the moment my work partially involves maintaining a legacy 16-bit Windows application that must run on every Microsoft OS from Windows 7 RC all the way back to Windows 95 (!). We only recently dropped support for Windows for Workgroups 3.11.
Because of this, I have become intimately acquainted with the 16-bit compatibility layer (NTVDM/WOW) in Windows NT4 and above which is the only thing keeping our app running in a 32-bit environment. Needless to say we are really glad Microsoft stands its ground on backward compatibility of its OSes.
I will be posting insightful retrospectives on investigations I have performed to keep a monolithic legacy code base able to run on modern machines and why on earth I would bother.