It is easy to take backward compatibility for granted on PCs, so much so that we rarely even use the phrase "backward compatibility". Most old games can run simply, and for other things, there is usually a compatibility mode built into Windows or DOSBox to get it running. This di

is easy to take backward compatibility for granted on PCs, so much so that we rarely even use the phrase " backward compatibility with ". Most old games can run simply, and for other things, there is usually a compatibility mode built into Windows or DOSBox to get it running. This did not happen by chance, as an old blog post from a former Microsoft programmer explained.

For example, when Microsoft wants users to switch to Windows 95, they don't even add specific code to find SimCity, which changes the way memory is allocated if it's running so the game doesn't crash.

This blog post was written by Joel Spolsky in May 2000, but was recently rediscovered by podcast and game producer Kal Yoshika on Twitter. Spolsky wrote "Chicken and Egg Problem", which means allowing users to adopt platforms without a large amount of software, and allowing software manufacturers to produce software for platforms without a large amount of users. Microsoft's solution, he said, is to make sure that old software can run -- including SimCity.

"Windows 95? No problem. Nice new 32-bit API, but it still runs old 16-bit software perfectly. Microsoft is fascinated by this and spends a lot of money to test every old program they can find using Windows 95," Spolsky wrote. "Jon Ross wrote the original version of SimCity for Windows 3.x, and he told me that he accidentally left a bug in SimCity where he read the memory he just released. Yes. It works fine on Windows 3.x because memory has never been leaked. ?

" Amazingly, SimCity didn't work properly in tests in the test version of Windows 95. Microsoft tracked this error and added specific code to Windows 95 to find SimCity in the computer. If it finds SimCity running, it runs the memory allocator in a special mode that does not release the memory immediately. This is the kind of obsession with backward compatibility that makes people willing to upgrade to Windows 95". Examples like

are not uncommon, for example, the first version of Final Fantasy 7 will crash if it runs on Windows NT instead of Windows 95, so Windows will lie to the game about the operating system it actually runs.