I found that working on Green Hills' Integrity was quite a bit easier than working in user space on a typical UNIX userspace. The primary reason is that the AP

I found that working on Green Hills' Integrity was quite a bit easier than working in user space on a typical UNIX userspace. The primary reason is that the API for Integrity was designed in the late 90's, where the POSIX API was inherited from the first thing folks thought of in the late 70's. The other aspect was that IPC via message passing is a very natural way to program.