2541	 An Overview of the ISPL Computer System Design	 This paper explores the advantages of the concurrent design of the language operating system and machine via microcode to create an interactive programming laboratory. It describes the synergistic effect that the freedom to move and alter features from one of these domains to another has had on the design of this system which has not been implemented . This freedom simplified both incremental compilation and the system s addressing structure and centralized the communication mechanisms enabling the construction of hierarchical subsystems. It also suggested an important new concept for operating systems separation of the scheduling from the maintenance functions in resource allocation. This separation enables incorporation of new scheduling algorithms decision of what to do without endangering the system integration correctly performing the scheduling decisions . concurrent design operating-system scheduling interprogram communication incremental compilation virtual addressing debugging hierarchical subsystems
