Truck Brakes

Alan Bomberger provides the following analogy concerning the design of brakes for the trailers of trucks. I remember the days when default universal privilege seemed correct. Universal privilege was the only way that people understood a computer running a program. The word ‘privilege’ was not even in the computer vocabulary. It was a great shock for some to imagine a physics program that could not merely write tape when it came to some point in the problem. That was about 1959. Things drifted to gradual limitation on what a program could do. Unix was an early but not the first system to define limitations inspired partly by CTSS which subdivided a 7090 among users with the primary end of giving each the illusion of his own computer. Privileges were very coarse then (and still). Root access meant you could do just about anything. Many programs were granted root access because of something they occasional needed to do. Today there are too many programs on my Mac with root privilege; and there is little they cannot do. When I try to install the new OCaml compiler the installer wants root privilege.