Overview

In 1945, mathematician John von Neumann, with the aid of J. Presper Eckert and John Mauchly, wrote a memo proposing the creation of an Electronic Discrete Variable Automatic Computer, more famously known as the EDVAC. In this paper, von Neumann suggested the stored-program model of computing. In the von Neumann architecture, a program is a sequence of instructions stored sequentially in the computer's memory. The program's instructions are executed one after the other in a linear, single-threaded fashion.

As time went on, advancements in mainframe technology expanded upon the ideas presented by von Neumann. The 1960s saw the advent of time-sharing operating systems. Run on large mainframe computers, these operating systems first introduced the concept of concurrent program execution. Multiple users could access a single mainframe computer simultaneously and submit jobs for processing. From the program's perspective, it was the only process in the system. The operating system handled the details of allocating CPU time for each individual program. At this time, concurrency existed at the process level, and the job of task switching was left to the systems programmer.

In the early days of personal computing, personal computers, or PCs, were standalone devices with simple, single-user operating systems. Only one program would run at a time. User interaction occurred via simple text based interfaces. Programs followed the standard model of straight-line instruction execution proposed by the von Neumann architecture. Over time, however, the exponential growth in computing performance quickly led to more sophisticated computing platforms. Operating system vendors...