1.4.1 Computer Architecture
The basic architecture of computers has had a profound effect on language
design. Most of the popular languages of the past 50 years have been designed
around the prevalent computer architecture, called the von Neumann archi-
tecture, after one of its originators, John von Neumann (pronounced “von
Noyman”). These languages are called imperative languages. In a von Neu-
mann computer, both data and programs are stored in the same memory. The
central processing unit (CPU), which executes instructions, is separate from the
memory. Therefore, instructions and data must be transmitted, or piped, from
memory to the CPU. Results of operations in the CPU must be moved back
to memory. Nearly all digital computers built since the 1940s have been based
on the von Neumann architecture. The overall structure of a von Neumann
computer is shown in Figure 1.1.