It's still possible to learn a lot of interesting things about old operating systems. Sometimes those things were documented, or at least hinted at, in blog posts that miraculously still exist. One such quirk showed up recently when someone noticed how Microsoft made sure that SimCity and other popular apps worked on Windows 95. From a report: A recent tweet by @Kalyoshika highlights an excerpt from a blog post by Fog Creek Software co-founder, Stack Overflow co-creator, and longtime software blogger Joel Spolsky. The larger post is about chicken-and-egg OS/software appeal and demand. The part that caught the eye of a Hardcore Gaming 101 podcast co-host is how the Windows 3.1 version of SimCity worked on the Windows 95 system. Windows 95 merged MS-DOS and Windows apps, upgraded APIs from 16 to 32-bit, and was hyper-marketed. A popular app like SimCity, which sold more than 5 million copies, needed to work without a hitch. Spolsky's post summarizes how SimCity became Windows 95-ready, as he heard it, without input from Maxis or user workarounds.
Jon Ross, who wrote the original version of SimCity for Windows 3.x, told me that he accidentally left a bug in the program. Yes, that's right. The memory didn't go anywhere on Windows 3.x. SimCity wasn't working in testing on the new Windows 95 versions. Specific code was added to Windows 95 to look for Sim City. If it finds SimCity, it uses a special mode that doesn't free the memory immediately. People were willing to upgrade to Windows 95 because of that obsession.
Spolsky considers this a credit to Microsoft and an example of how to break the chicken-and-egg problem.