All services must implement a file system interface for their service. The service's name space is mapped into the process's name space. There are files in each process-specific directory for the memory image of the process, the program text. There are also status and control files that show the state of the process and control the behavior of the process. When a user types CPU at a terminal, the terminal establishes a connection to a CPU server and runs a setup process.
All binary files contain byte-ordering descriptions to avoid ambiguities.
Because everything is a file, the only thing to protect is file access. They defend some of their design choices in the last section. They chose not to do lightweight processes explicitly, instead they try to make process allocation efficient and have multiple processes share the same address space. They don't do any fine-grained load balancing. They claim to be cost-efficient, although they depend on somewhat specialized multiprocessors for their CPU servers.