In the vast majority of modern computers, the same memory is used for both data and program instructions, and the von Neumann vs. The earliest computing machines had fixed programs. Some very simple computers still use this design, either for simplicity or buses in computer architecture pdf purposes.
Changing the program of a fixed-program machine requires rewiring, restructuring, or redesigning the machine. The earliest computers were not so much “programmed” as they were “designed”. With the proposal of the stored-program computer, this changed. One early motivation for such a facility was the need for a program to increment or otherwise modify the address portion of instructions, which had to be done manually in early designs.
One can “write programs which write programs”. This has allowed a sophisticated self-hosting computing ecosystem to flourish around von Neumann architecture machines. This is one use of self-modifying code that has remained popular. Whether he knew of Turing’s paper of 1936 at that time is not clear.
This was the first time the construction of a practical stored-program machine was proposed. At that time, he and Mauchly were not aware of Turing’s work. This drew him to the ENIAC project, during the summer of 1944. There he joined into the ongoing discussions on the design of this stored-program computer, the EDVAC. Neumann’s name on it, to the consternation of Eckert and Mauchly. The paper was read by dozens of von Neumann’s colleagues in America and Europe, and influenced the next round of computer designs.