Distributed Computing in Heterogeneous Environments

Distributed computing systems have received considerable attention in the last decade. Unfortunately, current research efforts are often restricted to homogeneous environments. There seems to be little attention for real-world installations, where heterogeneity is mostly the rule, rather than the exception. The Distributed Academic Computing Network Operating System, DACNOS for short, presents a general solution for running distributed applications in heterogeneous networks. The DACNOS extends local guest operating system services to provide homogeneous networking functionality. This is achieved by a virtual global object space, to which each user has access from within his native environment. This paper describes the architecture of the DACNOS network operating system, with special emphasis on its incarnation on the UNIX platform. It presents the DACNOS solutions to the problems of communication, access protection and data representation in a network of cooperating heterogeneous systems. DACNOS implementations currently exist for VM/CMS, VAX/VMS, PC-DOS, OS/2 and UNIX System V derivatives.