Lightweight shared objects in a 64-bit operating system

Abstract

Object-oriented models are a popular basis for supporting uniform sharing of data and services in operating systems, distributed programming systems, and database systems. We term systems that use objects for these purposes object sharing systems. Operating systems in common use have nonuniform addressing models, making the uniform object naming required by object sharing systems expensive and difficult to implement. We argue that emerging 64-bit architectures make it practical to support uniform naming at the virtual addressing level, eliminating a key implementation problem for object sharing systems. We describe facilities for object-based sharing of persistent data and services in Opal, an operating system we are developing for paged 64-bit architectures. The distinctive feature of Opal is that object sharing is supported in a runtime library, a,bove a single virtual address space that maps all primary and secondary storage in a local area network. This work was supported in part by the National Science Foundation under Grants No. CCR-8619663 and CCR8907666; by the Washington Technology Center; and by Digital Equipment Corporation through the Systems Research Center, DECwest Engineering, the External Research Program, and the Graduate Engineering Education Program. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notico is Siven that copving is bv permission of the Association for Computing Machinery. To copy otherwise. or to republish, requires B fee and/or specific permission. o 1992 ACM 0-89791.539.9/92/0010/0397...$1.50