Funny thing is, my old OS project [1] is more or less that - it could be a typical OS with separate tasks and so on, but it is effectively a single program, and

Funny thing is, my old OS project [1] is more or less that - it could be a typical OS with separate tasks and so on, but it is effectively a single program, and can easily be compiled as a single program with all the standard calls replaced with OS-level implementations. In practice, these are two different sets of use cases - in one you want clean abstractions, process separation, storing message passing and so on, in the other you want to get the call from your code into the libservice ASAP. Trying to (unwittingly) combine the two gave me quite a bit of grief. Another disadvantage is a lack of any protection (at least in my implementation), since everything shares the address space. Anyway, it's odd to see that a random idea i had 17 years ago is actually starting to get used. [1] http://orbides.org/aprom.php http://orbides.org/aprom.php