3.3. AIX

This information was supplied by Dirk Nitschke, as of August 1997, and describes how to install the LPRng package on a workstation running AIX 4.1.x and possibly 3.x.x as well. Dirk would be interested in any comments or corrections.

Printing on AIX systems is different. AIX provides a general queueing facility and printing is only one way to use it. You submit a print job to a print queue using one of the commands qprt or enq. You can use the BSD or System V printing commands lpr or lp, too. The qdaemon watches all (general) queues and knows how to handle your job. A (general) queue is defined in the file /etc/qconfig. The format of this file is different from the printcap format.

OK, how to replace the AIX printing system? There is no group daemon on AIX. Therefore you have to change the default group for file ownership and process permissions or create a daemon user and group. We decided to use the printq group; on reflection it would have been easier to have created a daemon group. The user daemon exists on AIX but we have chosen lpd as the user who runs lpd and all filters and owns the spooling directories. You can change the values for group and user in your lpd.conf file or in the sources src/common/vars.c. This is an example for lpd.conf:

    # Purpose: group to run SUID ROOT programs
    #   default group=daemon
    group=printq
    # Purpose: server user for SUID purposes
    #   default user=daemon
    user=lpd

Then stop all print queues defined on your workstation. Use

    # chque -q queuename -a "up = FALSE"

If you have local printers attached to your system you will have an lpd running. Stop this daemon using SMIT (Print Spooling, Manage Print Server, Stop the Print Server Subsystem). Choosing both also removes lpd from /etc/inittab. Maybe it's faster to do this by hand:

    h4: {75} # topsrc -p'pid of /usr/sbin/lpd'
    h4: {76} # rmitab "lpd"

Now delete all print queues managed by qdaemon defined on your system. You can use SMIT for this or the commands {mk,ch,rm}que, {mk,ch,rm}quedev, {mk,ch,rm}virprt. The SMIT fast path is smit rmpq.

To start the new lpd at system startup you have to add an entry to /etc/inittab:

    h4: {77} # mkitab "lpd:2:once:/full/path/lpd"

Some work has to be done if have have a local printer attached to your workstation. You have to create a device file like /dev/lp0. The SMIT fast path for this is smit mkdev. Choose Printer/Plotter, then Printer/Plotter Devices, then Add a Printer/Plotter. To create a parallel printer device select the following:

    Plotter type:              opp Other parallel printer
    Printer/Plotter Interface: parallel
    Parent Adapter:            ppa0 Available

    Port Number: p

    Send all characters to printer UNMODIFIED   no

and select yes! We have had a lot of trouble with no. This is very important! Expect erroneous output if you choose no. If you have already created a device file, change the characteristics! SMIT's fast path is smit chdev.

Finally remove all AIX printing commands like qprt, lp, cancel, lpq, and lprm. You will find a lot of them in /usr/bin. Do not remove enq and friends if you want to use the general queueing facility.

Now you can start your new lpd.