AN INPUT/OUTPUT ARCHITECTURE FOR VIRTUAL MEMORY COMPUTER SYSTEMS
David Draper Clark · DSpace@MIT (Massachusetts Institute of Technology) · 1974
In many large systems today, input/output is not performed directly by the user, but is done interpretively by the system for him, which causes additional overhead and also restricts the user to whatever algorithms the system has implemented. Many causes contribute to this involvement of the system in user input/output, including the need to enforce protection requirements, the inability to provide adequate response to control signals from devices, and the difficulty of running devices in a virtual environ-ment, especially a virtual memory. The goal of this thesis was the creation of an input/output system which allows the user the freedom of direct access to the device, and which allows the user to build input/output control programs in a simple and understandable manner. This thesis presents a design for an input/output subsystem architecture which, in the context of a segmented, paged, time-shared computer system, allows the user direct access to input/output devices This thesis proposes a particular archi-