> The fork+exec has many unobvious advantages over CreateProcess, What are the advantages you see, that are not rooted in the fact that it's very difficult to

> The fork+exec has many unobvious advantages over CreateProcess, What are the advantages you see, that are not rooted in the fact that it's very difficult to create any remotely sane declarative API in a language as imperative and primitive as C? In other words which of these advantages would still apply if you wrote your OS in, say, Ocaml? Splitting fork and exec allows you to roughly hew the process environment of a clone of the parent into shape, process state-wise, before you sacrifice it to birth the child-process which will inherit many of these desired (and generally a few undesired) traits. So one big advantage is that it allows you to re-use an existing (and growing!) set of imperative commands to modify aspects of a running process to specify the same aspects for a child process,and that piecemeal mutation is basically the only way to express anything of any complexity in C, particularly if you don't want to break API compatibility all the time. The downside is that you generally end up inheriting a bunch of cruft that you really didn't want to, that the imperative and piecemeal nature opens up problems with race conditions, and that there is a lot of overhead only partially mitigated by various complex hacks (COW, various more "leightweight" fork alternatives, special flags to general purpose system calls that are only there to control behavior upon forking, ...).