Jobs sent by the users are received by the printer and spooled. Multiple jobs can be received in parallel. At this state, jobs are visible via lpq and removable via lprm.
The spooled jobs are submitted to the PDL data processing module one at a time, in FIFO order. The PDL data processing module generates bitmaps for each submitted job.
When a job is fully ripped by the PDL unit it is removed from the Spool queue, and then will not be visible through lpq or removable through lprm. On the varioPRINT 140 Series, the job is visible on the local user interface as soon as spooling starts.
An LPD job can consist of multiple files. Each file in an LPD job will result in a separate request on the IBB. This makes each file visible in the mailbox as a separate document.
This allows a user to manipulate each document individually on the system console (print, delete, ...).
The file size information provided by lpq command represents the amount of data spooled on the printer for a given job.
Two situations can occur:
A PDL file is sent.
The size returned by lpq is equal to the size of the sent file.
A job that contains a job ticket data and PDL data is sent.
The size returned by lpq is the size of only the PDL file. This is because the job ticket is not spooled on disk.
This section describes which network traffic must be allowed for supporting the LPD protocol.
|
Protocol |
Source port |
Destination port |
Direction |
|---|---|---|---|
|
TCP |
Any |
515 |
Incoming |
|
TCP |
515 |
Any |
Outgoing |
When the LPD job reception is disabled, the LPD will no longer accept new jobs, but it will respond to lpq and lprm requests. The print server status as reported by lpq will indicate that reception is disabled.
New jobs are not accepted anymore when the amount of free space in the spool area falls below the low-water mark. If a spool-full is encountered while storing a job on the disk, the reception is aborted and the job deleted. The LPD protocol will cause the remote host to sent the job again later on.
All jobs of the printer spool queue will be restored after a restart/reboot/shutdown of the print server.
The LPD protocol will handle the recovery of jobs that were only partially received. The sending host will retransmit them when the print server becomes available again.
Multiple files that are submitted by one lpr command are treated as multiple jobs on the varioPRINT 140 Series. Jobs submitted through another interface will not be printed in between.
Multiple files are printed in the order they were received by the PRISMAsync Print Server. For example, the job contains a small file and a large file. Due to spooling at the host, the host can send the jobs in a different order than in which they were submitted.
A job can only be printed if it fits in the queue. If the job is too big for the spool area, the print server will not be able to accept it. The job then remains blocked in the lpd queue on the remote host.
If the job size is set to 0 or to a value above 125*10^12, the LPD supposes that the job size is unknown. In this case the job is always processed as a streaming job.
The Job ID that is shown to the user via lpq is the Job ID the print server has assigned to the job, not the Job ID the remote host originally assigned to it.
This is NOT conform the RFC standard. The Job ID that is displayed should be the one generated by the remote host.
Any application that stores the Job ID for future reference (e.g. print servers) will have problems tracking the jobs' progress. These applications consider the job as disappeared while the job is still queued but under a different Job ID. Also, an lprm using the stored Job ID will fail.