A successful Advanced Printing Software installation requires careful planning. You should consider the following questions before you create a print system:
What computers will host the server components?
What computers will host the client components?
Who are the users, operators, and administrators?
What name services should be used?
How will logical printers map to physical printers?
What job and document defaults do you need?
This chapter will help you answer these questions.
The chapter provides
only overview information.
It does not provide details on the commands to
install the software or create objects.
Detailed information on object creation
is provided in subsequent chapters of this guide and the
Advanced Printing Software Installation Guide
describes how to install
the software.
2.1 Setting Up Software Components
There are many ways to set up the print system software components.
This section helps you decide how and where to install client and server components,
how many servers to install, and how to ensure that all components can communicate
with one another efficiently.
2.1.1 Printer Configurations
You have a great deal of flexibility in the way you can configure servers,
printers, and queues in the system.
You can run all print system components
on a single host, or you can distribute them to run on hosts that are appropriate
to their function.
For example, you might choose to run server processes on
server hosts and print system clients on user workstations.
2.1.2 Multiple Server Hosts
Advanced Printing Software spoolers and supervisor can communicate with one another, even when they are located on different hosts. You might choose to run a supervisor on a host that is located near a set of direct-connected printers to facilitate cabling but run the spooler on a server host elsewhere in your building or site.
When you use more than one host to run print system components, you
need to distribute the names of the objects you create to all hosts that use
them.
2.1.3 Server Restrictions
The following restrictions apply to how you configure logical printers, physical printers, and queues on your print system spoolers and supervisors:
All logical printers associated with a queue must reside on the same spooler as the queue.
All physical printers on a supervisor can be associated only with queues and logical printers on one spooler.
2.1.3.1 Logical-to-Physical Printer Associations
When you configure printers, you can choose a close association or a
loose association between logical printers and physical printers.
2.1.3.2 Close Association
For some users, the concepts of and differences between logical printers
and physical printers might be difficult to understand.
Or, there might not
be a need to make the distinction between logical printers and physical printers.
In these cases, create a logical printer, a physical printer, and a printer's
queue as tightly-bound triplets that work together as one printer.
Thus, every
output device is represented by exactly one of each of these objects.
2.1.3.3 Loose Association (Fan-in and Fan-Out Queues)
If you need flexibility in your printing environment that allows changing printer configurations with minimal disruption to users, then you might want to take advantage of the logical and physical printer abstractions.
For example, you might have several similar output devices in a printer room, all with the same capabilities. Associating the physical printers with one queue implements a load-sharing configuration, where users submit jobs to one logical printer, and the system picks the next available device for printing. In such a configuration, sometimes called a fan-out queue, individual printers can be serviced, extra printers can be configured, or surplus printers can be removed, without affecting the user.
A fan-in queue configuration is several logical printers funnelling jobs to one queue. You might choose to set up logical printers with specific default job and document options, using initial-value objects. Each should have unique job processing capabilities. For example, you could set up a logical printer that always prints text documents one-up in portrait mode, and another that prints such documents two-up in landscape mode with line numbers. By associating each of these logical printers with one queue, the system directs the documents submitted to the one or more physical printers associated with that queue.
Fan-in and fan-out queues can be used together to provide a high degree
of flexibility and convenience.
2.1.4 Using Multiple Supervisors on a Single Host
If you intend to support more output devices from one server host than
is specified by the
maximum-number-of-printers-supported
server attribute, use more than one supervisor process and object.
You might
wish to support more than one supervisor, even before you reach the maximum
number, for the following reasons:
Heavily loaded server processes constitute a single point of failure, should the server host go down.
Creating less than the maximum gives you more flexibility for reconfiguring the system as needs change.
Heavily loaded server processes can be less responsive, making them more difficult to swap, and swapping affects more printers.
2.1.5 Using Supervisors on Direct-Connected Printers
Some output devices are connected through a serial port or parallel
port that is attached directly to a host system's hardware.
Advanced Printing
Software requires that you run a supervisor process on any host that has such
direct-connected printers.
If, in your environment, several such printers
are connected to users' workstations, each workstation will need to run a
supervisor process.
Administrators of those workstations can choose whether
to associate the physical printers with queues on a central spooler or on
several distributed spoolers.
2.2 Planning Name Services
As the servers, queues, and printers become more numerous, assigning, managing, and distributing unique object names becomes a more complex task. In this environment, it might be benficial to use Network Information System (NIS) software to distribute a centrally managed printer object name map.
See
Chapter 3, for more information about printer
configuration files and the Network Information System software.
2.3 Event Notification
The print system architecture provides methods for notifying end-users, operators, and administrators when events occur in the printing system.
See
Chapter 9
for more information.
2.4 Security
Security features can be used to control access to job data and management functions. These features perform authentication and authorization checks on every operation request to ensure that only authorized users obtain access to Advanced Printing Software.
Authentication is the process of validating that users are who they claim to be.
Authorization is the process of ensuring that an authenticated user has the permission required to perform specific operations.
Three privilege levels for users identify the permissions allowed them:
End user
Operator
Administrator
The privilege levels have an access order. An administrator can configure objects plus perform all of the tasks that an operator can. An operator can control printing plus perform all of the tasks that an end-user can.
The print system uses the
access-control-list
attribute
to specify the privilege level for each user.
Authentication compares the
user identifier (UID) in the domain's password file for the user who initiated
the operation request to the entries in the
access-control-list
attribute.
If the comparison is successful, authorization then checks the
access-control-list
attribute for the user's privilege level.
2.5 Configuration Tasks
This section provides an overview of the tasks you need to complete to initially configure and start your print system. The tasks are listed in the order that you should complete them and include the mandatory tasks as well as the optional tasks you can perform.
Each task is described briefly and contains a reference to other sections in this document that describe in detail how to perform the task.
Create and configure servers, spoolers, and the LPD Outbound Gateway servers.
Refer to Chapter 5 for information on creating and configuring servers.
Refer to Chapter 11 for information on creating and configuring the LPD Outbound Gateway.
Create and configure queues and printers.
Refer to Chapter 6 for information about creating and configuring logical printers, physical printers, and queues.
Set up name service.
Refer to Chapter 3 for more information on setting up the naming service that you will use to support your system.
Set up security.
Refer to Chapter 4 for more information on print system security.
Optionally, set up event notification.
Refer to Chapter 9 for information on setting up event notification.
The Advanced Printing Software kit includes a character-cell, menu-driven
script that administrators can use to configure a working print system.
The
script is supplied in the
/usr/pd/scripts/pd_get_started
directory and must be run by the root user when creating new print objects.
Use the
pd_get_started
script to create spooler and
supervisor processes, logical and physical printers, queues, and associated
initial-value objects.
It also provides a means for starting and shutting
down server processes and for displaying your local server configuration.
This script is not intended for everyday administration of Advanced
Printing Software.
It is most useful for getting your system up and running
quickly.
The CDE
pdprintadmin
GUI tool is more appropriate
for ongoing print system administration.