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Chapter 5 Configuring the Internal Ethernet Adapter for TCP/IP
168
npd locks
As npd acquires an exclusive lock on the Internal Ethernet Adapter
port, it is possible to lock out other daemons that may reside on other
UNIX hosts. Therefore, npd is designed to timeout and release the lock
if the pseudo-tty pair is idle for a specified time (30 seconds). You can
modify this value with the -t option.
npd -t 60 /dev/spike.prn spike prn
for the timeout to occur in 60 seconds.
Testing npd
Once npd has been started, test to see if npd is working before
attempting to print through the spooler. The following is one test
method:
cat test.txt > /dev/spike.prn
redirects the cat output of test.txt to the npd device /dev/spike.prn
which is then sent to the Internal Ethernet Adapter named spike.
Modifying a Host to Use npd
If you want the npd daemon to start every time you reboot your UNIX
machine, edit your -rc file to include the appropriate npd startup
command (from the previous section). After npd starts, integrate the
print spooler into this pseudo-tty setup.
In BSD print spooler systems, modify the lp= field in the appropriate
printer entry in /etc/printcap file. Set lp= to the
devicefile
argument of
the npd program.
On System V systems, the -v option in the lpadmin command will equal
the
devicefile.
Stopping npd
Whenever an npd daemon starts, it makes a log entry in the /usr/adm/
npdlog file. The contents of this file have the following naming
information:
pid ipname port masterfile slavefile devicefile