[gaius]

Yes, kernels are not difficult because most of the problems are purely technical problems, that programmers can just decide for themselves any ambiguities, and many of the parts can be worked on separately. Software with users is 10-100x more difficult.

http://c2.com/cgi/wiki?WhyIsPayrollHard

[cgh]

Sorry if I was unclear. I was just using Linux as an example. The product I work on has plenty of users. I don't agree that it's orders of magnitude more difficult but that's beside the point.