[Eridrus]

> I don't understand the physics of a harddisk, or the pipelining of a CPU, or some of the low level OS functionality.

I think the key difference is that you don't need to know how that works. I think there's a question of how leaky the abstraction is and how often you need to look behind the curtain.

[goldbrick]

Tons of people and use cases never need to delve into the implementation to get a lot of mileage out of Rails. I get a lot of work as a Rails consultant and most of the real pain I see is caused by people doing stuff like implementing their own ORM with an ActiveRecord-ish interface, or writing their own caching logic implemented as a mixin for ActiveRecord.