Process semantics and abstraction problems on Linux, Windows, MacOS, Posix.

This article documents process semantic differences between Linux, Windows, MacOS, Posix including what can be reasonably relied on and what no.

TODO motivation: audience/why this is actually relevant to read, ie security.

IPC.
    Signals.
    Pipes.
    Sockets
    Shared memory.
    Shared memory.
Security.
    File access permissions.
    User permissions.
    TODO.
Process groups.

IPC.
Posix.
Process groups.