Should a programmer also know about FS block sizes? About ethernet size? About Multithreading? Memory access bandwidth? CPU architecture? Stored procedures in a DB? Current encryption schemes?

I would say it depends totally on the tasks of the coder. If you fiddle around with some ASP: NO. If you are squeezing every last bit for Netflix performance: YES.

Our domain is so incredibly huge, deep, wide & divers that I do not expect regular coders to be familiar with most details.