Microsoft research: A fork() in the road

The paper gives several motivations, but I reckon the primary one comes from the authors' work as OS researchers interested in making new research operating systems. Currently, fork() usage is so prevalent in UNIX software that they are faced with implementing fork() (which they claim - I see no reason to doubt their experience in this area - infects the entire OS design) or have an OS that can't run huge amounts of existing software out there (removing a valuable testing resource and possible adoption path for the OS).

It's notable that S7 only suggests the OS might be rewritten to not have fork() as a core syscall after the most important software (however you want to define that, I guess) has been rewritten to avoid it. They're a little vague on how either part of that process would happen, but the purpose of the paper is just to convince people that it should be done, not set out a plan for achieving it.