Researchr is a web site for finding, collecting, sharing, and reviewing scientific publications, for researchers by researchers.
Sign up for an account to create a profile with publication list, tag and review your related work, and share bibliographies with your co-authors.
Michael D. Schroeder, Jerome H. Saltzer. A Hardware Architecture for Implementing Protection Rings. Communications of the ACM, 15(3):157-170, 1972.
Abstract is missing.