Real Time in a Real Operating System

Now more than ever, the quality of an operating system is more a subject of religious debate than of technical merit. The Windows community is like the Catholic Church; it has the largest following, its rituals are the most baroque and Bill Gates is as infallible as the Pope. The Unix community is like the mainstream protestant church; it has quite a large following, rituals which, by and large, make sense and, if they don’t anymore, they once did. Like the protestant church, there are many flavors of observance: Linux, FreeBSD, NetBSD, Mach, the list is as long as the list of protestant variants. Linux is more evangelical than the others, but this is a good protestant trait. The Mac community hangs somewhere in the lurch between Windows and Unix, the Catholics and the Protestants, a bit like the Anglican Church; they’re Protestants acting like Catholics. Plan 9 from Bell Labs is like the Quakers: distinguished by its stress on the ‘Inner Light’, noted for simplicity of life, in particular for plainness of speech. Like the Quakers, Plan 9 does not proselytize. Plan 9 is relatively little known and has but a small user community (a few thousand installations). Nevertheless, it is a complete operating system and it is the only operating system booted by many of its users. Plan 9 is also used in several embedded environments. For instance, it is the system inside the Viaduct, a computer system the size of a packet of cigarettes that provides an encrypted bridge between Lucent employees’ home computer and the corporate intranet. It is also beginning to find use in experimental wireless base stations. New technologies (the printing press, organ transplants, birth control) and changing world views (the solar system, evolution) have always been upsetting to churches, causing violent debates and schisms. This is just