Specifications

Distributed Computing Support
3.4 Distributed Application Support
The DCE for OpenVMS product family supports the following networking
transports: TCP/IP, User Datagram Protocol (UDP), and DECnet Phase IV.
The DCE for OpenVMS products include:
• DCE Runtime Services for OpenVMS, required for all systems participating in
the DCE cells. A DCE cell is the term used to describe the group of systems
that participate in the distributed computing environment. The runtime
services kit includes DCE client functions and DCE administration tools.
• DCE Application Development Kit for OpenVMS, required for those
developing distributed applications but optional for other users. The kit
provides users with an Interface Definition Language (IDL) for writing
remote procedure calls.
Digital is committed to support the following DCE products on OpenVMS:
• DCE Cell Directory Server (CDS), a central repository containing information
about the location of resources in the DCE cell. The CDS server allows access
to resources by a single name, regardless of physical location. One CDS
server is required for each DCE cell.
• DCE Security Server, which protects resources from illegal access by
providing authentication and authorization services and provides for secure
communications within and between DCE cells. One Security server is
required for each DCE cell.
3.4.2 ObjectBroker
ObjectBroker, formerly named DEC ACA Services, enables developers to use
an object-oriented design to integrate independently-developed applications
across heterogeneous environments. ObjectBroker facilitates the transition to
client/server computing and reduces the cost of developing new client/server
applications. ObjectBroker is available for OpenVMS VAX and OpenVMS AXP
systems.
ObjectBroker complies with the Object Management Group’s (OMG) Common
Object Request Broker Architecture (CORBA) and provides both dynamic and
static interfaces for greater user flexibility.
ObjectBroker extends the Microsoft Dynamic Data Exchange (DDE)
communication protocol to allow Microsoft Windows applications on a networked
PC to interact, using DDE, with applications running on ULTRIX, OpenVMS, and
SunOS. ULTRIX, OpenVMS, and SunOS applications can function as DDE clients
and servers. DDE support in ObjectBroker allows two Microsoft applications to
communicate on different PCs.
3–6