[whartung]

It’s useful in a world of several processes sharing things. This is much less common today in a world of “single process” containers and VMs as well as monolithic processes using threads or async techniques.

However, Java can build a special library file of the core JRE classes that it can mmap into memory with the intent to speed up startup times, mostly for small Java programs.

Guile scheme will mmap files that have been compiled to byte code. You can visualize a contrived (especially today) scenario where Guile is used for CGI handlers, having the bulk of their code mapped, the overall memory impact of simultaneous handlers is much lower, as well as start up times.

The process model is less common today so the value of this goes down, but it can still have its place.