Background: Distributed Computing and OSF DCE

Most corporate managers and technical professionals recognize the merits of distributed computing. A network of small, cooperating systems is a sensible alternative to a large, centralized system. In distributed networks, disparate systems share resources and data rather than operate independently, eliminating the duplication of special-purpose hardware and software. Distributed systems are historically more reliable and available. Efficiency, interoperability, extensibility, availability, economy of scale and other benefits make distributed computing a practical, cost-effective solution.

While the advantages of distributed computing are indisputable, implementing an effective network can be daunting. This is especially true if the network incorporates diverse platforms that are expected to share data and interoperate seamlessly.

A solution is the Open Software Foundation (OSF) Distributed Computing Environment (DCE). DCE is a comprehensive, integrated set of tools and services that support the creation, use, and maintenance of distributed applications in a heterogeneous computing environment. Applications developed with DCE tools are portable to other DCE platforms. In addition to running distributed applications, DCE services enable and enforce platform interoperability and secure, uniform access to shared data and resources.

DCE Core Services

The following are the fundamental service components of a DCE cell:

Cell Directory Service (CDS): CDS stores, retrieves, and maintains information about the computing services available to the cell's users and applications (principals). The information is stored in a central repository called the CDS namespace. CDS looks up a service's information, such as a print service's network address and physical port number, on behalf of authorized principals.
Security Service: The Security Service consists of services and facilities that secure communications within the cell and control access to cell services and other resources. The Security Service manages principal authentication and authorization and maintains the security registry, which is the central database for registering principals.
Distributed Time Service (DTS): DTS synchronizes the clocks on the systems that make up the cell.
Remote Procedure Call (RPC): RPC, which consists of Run-time Services, a daemon, and a control program, enables communication between DCE client and server processes, maintains the endpoint map, and accesses RPC data in the CDS namespace. The endpoint map is a database on each host containing the addressing (binding) information of every instance of each local computing service (RPC server) advertised in the CDS namespace. RPC completes the partial binding information that principals obtain from the namespace.

What is a cell?
A cell is a logical segment of your distributed network
or the entire network. It is a group of computers (DCE hosts)
that share a common security registry, CDS namespace, and
computing services. Each host runs a set of DCE core service
daemons (server and client processes). These processes make it
possible for principals to access the computing services
advertised in the CDS namespace.

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Last updated and validated Tue 30 Jan 96 by nita@halsoft.com