Nine AM to five AM. :D It has ever been so because there is no other way to design and build complex technical software.

I don't recall whether it was the OS team at Microsoft or Apple, but it doesn't matter. They had T-shirts that read "Working 80 Hours A Week And Loving It".

Well, when I was a young system programmer I worked roughly 14x7 or roughly 100 hours per week. The degree of concentration required to have multiple people design and build a complex piece of software requires that at least the architect/designer/manager work these kinds of hours.

While I can no longer put in 48-hour days the way I used to, even today I do most of my work at night because that's when I am free of interruptions and distractions and can concentrate on the technical work.

So what is a system programmer? Well, one of the Microsoft marketing guys referred to one of their system programming groups as "The guys who do their taxes in hexadecimal." :D