Comment by jiggawatts

Bad... how?

From my perspective watching the various techniques used by a multitude of operating systems over many decades, the Windows-style process+thread model seems to be winning out over the UNIX fork() model.

For example, PostgreSQL seems to suffer greatly from the "forked process per connection" model, necessitating front-ends that do connection pooling. Database engine after database engine seems to go through this phase and then "upgrade" to either a single-process thread pool model, or start using async IO in some way. (Web servers also.)

For reference, Microsoft SQL Server back in the 1990s could on Windows NT 4 could handle more connections than PostgreSQL in 2020...