The pmadm command enables you to administer port monitors' services. In particular, you use the pmadm command to add or remove a service and to enable or disable a service. You can also install or replace per-service configuration scripts, or print information about a service.
Each instance of a service must be uniquely identified by a port monitor
and a port. When you use the pmadm command to administer
a service, you specify a particular port monitor with the pmtag argument,
and a particular port with the svctag argument.
For each port monitor type, the SAF requires a specialized command to format port monitor-specific configuration data. This data is used by the pmadm command. For ttymon and listen type port monitors, these specialized commands are ttyadm and nlsadmin, respectively.
Whenever you attempt to log in by using a directly connected modem or
alphanumeric terminal, ttymon goes to work. First, the
SAC process is started by SMF. Then, the SAC automatically starts the port
monitors that are designated in its administrative file, /etc/saf/_sactab. After the ttymon port monitor has been started,
it monitors the serial port lines for service requests.
When someone attempts to log in by using an alphanumeric terminal
or a modem, the serial port driver passes the activity to the operating system.
The ttymon port monitor notes the serial port activity,
and attempts to establish a communications link. The ttymon port
monitor determines which data transfer rate, line discipline, and handshaking
protocol are required to communicate with the device.
After the proper parameters for communication with the modem or terminal
are established, the ttymon port monitor passes these parameters
to the login program and transfers control to it.
When an instance of the ttymon port monitor is invoked
by the SAC, ttymon starts to monitor its ports. For each
port, the ttymon port monitor first initializes the line
disciplines, if they are specified, and the speed and terminal settings. The
values used for initialization are taken from the appropriate entry in the /etc/ttydefs file.
The ttymon port monitor then writes the prompt and
waits for user input. If the user indicates that the speed is inappropriate
by pressing the Break key, the ttymon port monitor tries
the next speed and writes the prompt again.
If autobaud is enabled for a port, the ttymon port monitor tries to determine the baud rate on the port automatically.
Users must press Return before the ttymon port monitor
can recognize the baud rate and print the prompt.
When valid input is received, the ttymon port monitor
does the following tasks:
Interprets the per-service configuration file for the port
Creates an /etc/utmpx entry, if required
Establishes the service environment
Invokes the service associated with the port
After the service terminates, the ttymon port
monitor cleans up the /etc/utmpx entry, if this entry
exists, and returns the port to its initial state.
If a port is configured for bidirectional service, the ttymon port
monitor does the following:
Allows users to connect to a service
Allows the uucico, cu, or ct commands to use the port for dialing out, if the port is free
Waits to read a character before printing a prompt
Invokes the port's associated service, without sending the prompt message, when a connection is requested, if the connect-on-carrier flag is set