I guess the author didn't use that many other programming languages or OSes. You can do the same even in garbage collected languages like Java and C# and on Windows too.

https://docs.oracle.com/javase/8/docs/api/java/nio/MappedByt...

https://learn.microsoft.com/en-us/dotnet/api/system.io.memor...

https://learn.microsoft.com/en-us/windows/win32/memory/creat...

Memory mapping is very common.