OSF DCE Application Development Guide--Core Components

OSF DCE Application Development Guide—Core Components
Of course, in a distributed environment, these data and services must be easily yet
securely accessible from other hosts. The DCE host daemon (dced) is a continuously
running program on each host that provides access to the host services either locally on
that host or remotely from another host.
2.1 Types of Applications
Although applications may need some aspect of these host services (control over which
services are enabled for a particular server, for example), typical servers do not have to
do any special coding for them. This reduces the size and complexity of server code and
keeps the details of administration out of applications. It also removes the burden of
server administration so you can concentrate on the application’s business functionality.
System administrators will appreciate this development model too because it is unlikely
that many servers implementing their own administrative mechanisms will all behave in
the same manner. Administrators commonly use the DCE control program, dcecp,to
access the host services (via dced) of any host in their distributed environment (provided
the user has the appropriate permissions). The DCE control program also uses a script
language for more sophisticated administration. See the
for more on using dcecp to access the host services.
Although dcecp commands offer an administrator a great deal of control over DCE hosts
and servers, a set of APIs are also supplied for application developers who need to access
the DCE host services from an application rather than from scripts or the operating
system’s command line.
Typical business applications do not use the APIs of these services, but a management
application might. A management application is a client or server that manages other
servers or some aspect of the distributed environment. (The dced program is itself a
management application that is built into DCE.) Some other types of applications that
might use these API include
• Applications that control other servers for load balancing or server redundancy.
• An application that uses a graphical user interface (GUI) instead of the command-
line interface provided by dcecp.
• An application that needs to monitor a server’s current state. For example, an
application may need to make sure a particular server or one of its services is
available.
2.2 Issues of Distributed Applications
The most important aspect of dced is that it gives system administrators the ability to
remotely manage services, servers, endpoints, and even objects on any host in DCE.
This eliminates the frustrating and tedious task of logging into many different hosts to
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