What were the early operating systems commonly known as,

Solution

Early operating systems were commonly referred to as "residence monitors." These systems were designed to manage and monitor the execution of programs, essentially overseeing the activities of the computer while it was in use. The primary role of these residence monitors was to provide basic control over system resources and ensure that programs could run efficiently within the constraints of the hardware available at the time. Unlike modern operating systems that offer extensive functionalities and user interfaces, residence monitors were focused on the fundamental task of managing program execution and ensuring that the system's resources were utilized effectively.