Opal: A Single Address Space System for 64-bit Architectures

The recent appearance of architectures with flat 64-bit virtual addressing opens an opportunity to reconsider the way our operating systems use virtual address spaces. We are building an operating system called Opal for these wide-address architectures. The key feature of Opal is a single global virtual address space that extends to data on long-term storage and across the network. In this paper we outline the case for the use of a single virtual address space, present the model of addressing and protection used in Opal, and discuss some of the problems and opportunities raised by our approach.