The DTC Device File Access Utilities are a group of configuration
files, executable files and one or more daemons. Together these
utilities allow the HP 9000 system administrator
to set up logical pairs of pty device files and physical ports on
the DTC or other server. Once this is done, the server's pty devices
can be accessed in the same way as MUX-connected tty devices
can.
These ptys can be assigned to "incoming" connections
or to "outgoing" connections . Incoming connections to the
system are initiated by input devices attached to the server (such
as terminals), while outgoing connections are initiated by the system
to output devices attached to the server (usually printers). When
an application on the system opens one of these device files, the
DDFA Utilities transparently manage the creation of a Telnet connection
to the associated server port and its device.
Configure and execute the DDFA Utilities in two simple steps:
Edit the Dedicated Port configuration file (dp)
to add an entry for each physical terminal server port which describes
the association to a unique pty device filename.
Run the Dedicated Port Parser program (dpp)
to parse the dp file and to execute an ocd
process for each outgoing connection defined in the dp file.
Each time the HP-UX system initiates an outgoing connection
to a pre-defined terminal server port, its unique Outgoing Connection
Daemon (ocd) becomes active. It then establishes
the Telnet connection and manages it until the connection is closed.
Figure 2-1 shows how the system, the DTC terminal server,
and the DDFA Utilities interact with one another.
![[HP 9000 and DTC Interaction With DDFA]](img/gfx1.gif)