darrell@sdcsvax.UUCP (03/13/87)
I understand that there has been some discussion in this newsgroup recently regarding the Cronus Distributed Operating System, which is currently being developed by BBN for RADC. I'd like to add some information, and offer a point of contact for those desiring more. The Cronus project started in 1981, and the system has been running at BBN for about 3 years. It is also running at RADC and NOSC, with additional installations planned. Cronus is currently supported on several flavors of Unix, VAX/VMS, bare MC68000 "generic computing elements", and Symbolics Lisp Machines (using Common Lisp -- the other implementations use C). Cronus differs from other distributed operating system efforts in 3 major ways: It operates in a heterogeneous computing environment (w.r.t. hardware, programming languages, and network technology). It stresses interoperability with existing non-distributed operating systems, tools, and applications. (The Newcastle Connection-style file "trapping" facility mentioned in a previous message is but one example of this.) It's intended as a base for the large-scale development of complex distributed applications, with a comprehensive system model, automated development tools, and a variety of baseline services. The cornerstone of Cronus is a Smalltalk-like object model. System and application resources are instances of some object type, and are under the control of one or more managers for that type scattered throughout the network. Clients affect objects by invoking operations (determined by the type) upon them. Managers implement these operations using the local programming languages, conventions, and services of the underlying host. The object model provides the basis for interprocess communication, location transparency, migration and replication, high-level resource management, access control, and problem decomposition. Cronus currently supports about 30 different managers, providing a variety of system, administration, software development, and application services. Several papers describing Cronus were presented at the 6th Intl. Conference on Distributed Computing Systems, held in Boston in May 1986. Proceedings are available from the IEEE (catalog number 86CH2293-9). I'd also be happy to answer any questions or provide additional information. Mike Dean BBN Labs mdean@bbn.com (Internet) ...!seismo!bbn.com!mdean (uucp)