input: [0] 1. [UNIX] Everything is a File or a Process. The most basic underlying concept in UNIX is the file. In general, bits are not mediated, and the basic conceptual role of a program is creating, deleting, and revising files rather than interacting with objects that have behavior. Many of the key objects in the system are ``passive.'' [EROS] 
output: Everything is an Object. Conceptually, all entities in a running EROS system are objects that are implemented by some server process. Kernel-implemented services attempt to preserve this conceptual illusion. From the programmer perspective (and, to a large extent, the kernel perspective) there are no unmediated bits in the system. Fundamentally, the majority of the objects in the system are ``active,'' by which I mean that they execute instructions.