Technical data

Clients make requests to submit print jobs to named printers. The
spooler puts the job in a queue associated with the printer and applies
initial-value-job and initial-value-document attributes to the job
and its documents, respectively. The spooler stores the job’s document files
in a spool directory, where it is accessed by or delivered to a supervisor.
When the associated physical printer is ready to accept the job, the spooler
transfers the job to the supervisor for printing.
1.2.2.2 Supervisor
The supervisor, pdspvr, controls and communicates with output devices
connected directly to a host or through network connections. It is responsible
for sending document data to the output device and for returning and
reporting status information about job progress while the job is in the
printing state. It can also report when the device is not responding to
communication attempts.
A supervisor process can control and communicate with as many as 50
output devices of various types and connection methods. Depending on the
printer, its native language, and its connection capabilities, the supervisor
offers bidirectional communication, flexible device control, multiple printer
languages, filters that can translate or modify the document data stream,
and optional formatted separator pages.
1.2.2.3 LPD Outbound Gateway Supervisor
The LPD Outbound Gateway Supervisor, pdspvlpr, allows users to
submit print jobs to existing lp or lpr printers or print systems in your
environment. You can submit jobs to an LPD queue and remove jobs that
have not already printed from the queue.
1.2.3 Server Daemons
The Advanced Printing Software includes the following daemon programs
that work on behalf of the client interfaces and server programs:
• Protoserver (rpc.pts)
• Notification Server (pdntfs)
• Console Notification Daemon (pdconntf)
The protoserver daemon serves as the server registration and lookup
agent for spoolers and supervisors running on a host. Clients must
first communicate with a host’s protoserver to acquire the RPC binding
information for servers specified in an operation. The protoserver registers
itself on a host using a fixed, registered program number.
Advanced Printing Software Overview 1–9