NAME

ttyd − TTY daemon

SYNOPSIS

/usr/etc/ttyd

DESCRIPTION

ttyd can be started to handle the processing of interrupts from devices on (H)VIOCs and devices on the async ports of the MPCC communications controller.  When ttyd is not started, tty interrupt processing is either handled immediately in an interrupt routine or is queued for later processing by the softclock interrupt. 

ttyd is started by uncommenting the appropriate line in /etc/rc.  System administrators may wish to review the run options specified in /etc/rc and change them as needed.  Note that once ttyd is initiated, it can not be killed. 

When the ttyd program is used to process tty interrupts, the priority of the daemon can be set so that the most important real-time processes on that processor have a higher priority than tty interrupt processing.  Care must be taken in setting the priorities of tasks to be higher than the ttyd program, since data from ttys may be lost if the ttyd process is prevented from running for lengthy periods of time.  Processes which require a high degree of responsiveness can be scheduled at priorities higher than ttyd. 

ttyd will fail if it is not started by the super-user or an instantiation of ttyd exists. 

SEE ALSO

tcpipd(1M), softclockd(1M),
CX/RT Reference Manual

CX/UX Administrator’s Reference