To let the AppleTalk printing service run correctly under the A/UX BSD printer spooler (/usr/lib/lpd, lpr, ...), the following files under each printer directory (for example /usr/spool/lpd/AppleTalk) should be owned by user "daemon" and group "daemon":
drwxrwxr-x 2 daemon daemon .
drwxrwxr-x 7 daemon daemon ..
-rwxr-xr-x 3 daemon daemon ifilter
-rwxr-xr-x 3 daemon daemon ofilter
-rwxr-xr-x 3 daemon daemon nfilter
prw-rw---- 1 daemon daemon pipe
The error message "...: pipe: cannot open" most likely indicates that the ownership or groupship of any of the above files might have been incorrectly set. Check yours, correct them, then restart the "lpr" command.
Because "lp" is the default printer in the BSD printer spooler system, the "lp|at|AppleTalk" entry in /etc/printcap is chosen by the printer daemon (/usr/lib/lpd). /usr/lib/lpd then passes all input file(s) to be printed to a remote PAP (Printer Access Protocol) server for printing. This is done by the input/output filter programs (ifilter, ofilter) provided under individual printer directory (/usr/spool/lpd/AppleTalk), which is in turn invoked by the "atprint" program which directly copies data to a remote PAP server.
Under "lpr", the destination PAP server is chosen as follows:
If the -Pprinter option of "lpr" command or the environment variable PRINTER is used or set, then the output goes to a specific printer. Otherwise, the system-wide default printer, the "lp" entry in /etc/printcap, is chosen, which is also the AppleTalk printer. The default AppleTalk printer is then chosen via the Chooser, from the Control Panel, or through the at_cho_prn utility.
We assume that you have correctly configured and set the AppleTalk in A/UX kernel.
Article Change History:
09 Sep 1994 - Reviewed.
31 Aug 1992 - Reviewed.
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