From Monitors to Monitors: A Primitive History

Abstract As computers became multi-component systems in the 1950s, handling speed differentials efficiently was identified as a major challenge. The desire for better understanding and control of ‘concurrency’ spread into hardware, software, formalism. This paper examines way which problem emerged handled across various computing cultures from 1955 to 1985. In machinic culture late system programs called ‘monitors’ were used directly managing synchronisation. Attempts reframe synchronisation subsequent algorithmic pushed higher level abstraction; Dijkstra’s semaphores reaction algorithms’ complexity. Towards end 1960s, ‘structured programming’ created milieu Dijkstra, Hoare, Brinch Hansen (among others) aimed concurrency primitive embodied new view programming. Via conditional critical regions ‘secretaries’, co-produced ‘monitor’ appeared provide desired encapsulation. construct received embodiment few programming languages; this ends by considering Modula Concurrent Pascal.