Hardware architectures for programming languages and programming languages for hardware architectures

Programming Languages and Operating Systems introduce abstractions which allow the programmer to ignore details of an implementation. Support of an abstraction must not only concentrate on promoting the efficiency of an implementation, but also on providing the necessary guards against violations of the abstractions. In the frantic drive for efficiency the second goal has been neglected. There are indications that recent designs which are claimed to be both simple and powerful, achieve efficiency by shifting the complex issues of code generation and of appropriate guards onto compilers.Complexity has become the common hallmark of software as well as hardware designs. It cannot be mastered by the common practices of testing and simulation. Hardware design may profit from developments in programming methodology by adopting proof techniques similar to those used in programming.