Technical data

Setting Up and Maintaining Queues
14.1 Understanding Queuing
14.1.2 Understanding Classes and Types of Queues
In general, queues can be divided into two classes:
Class Description
Execution queues Queues that accept batch or print jobs for processing.
Generic queues Queues that hold jobs until an appropriate execution queue
becomes available. The queue manager then requeues the job to
the available execution queue.
The following sections provide more details about execution and generic queues.
14.1.2.1 Execution Queues
Descriptions of types of execution queues follow:
• Batch execution queues accept only batch jobs. A batch job executes as a
detached process that sequentially runs one or more command procedures.
The user defines the list of command procedures when submitting the job.
• Output execution queues accept jobs that a symbiont processes. The queue
manager sends the symbiont a list of files, which the user defines when
submitting the job. An output symbiont transfers data from a disk to an
output device. As the symbiont processes each file, it produces output for the
device it controls, such as a printer or a terminal.
The operating system provides a standard print symbiont named PRTSMB,
which prints files on hardcopy devices. The LAT print symbiont LATSYM
prints files on output devices attached to LAT ports. You can also design
symbionts for this or any other file-processing activity that the OpenVMS
batch and print queuing system manages. (Refer to the OpenVMS Utility
Routines Manual for more information.)
Output execution queues include the following types:
Type Description
Printer execution queue Uses a symbiont to direct output to a printer.
Terminal execution queue Uses a symbiont to direct output to a terminal
printer.
Server execution queue Uses a user-modified or user-written symbiont to
process the files that belong to jobs in the queue.
When you create an output execution queue, you designate it as either a
printer, a terminal, or a server execution queue; you can also specify the
symbiont to be associated with the queue. However, when the queue is
started, the symbiont process associated with the queue can override the
queue designation if the queue type specified does not match the type of
device.
The standard symbiont provided with the operating system determines
whether it is controlling a printer or a terminal. The symbiont communicates
this information to the queue manager, which, if necessary, changes the type
designation of the output execution queue. By convention, a user-written or
user-modified symbiont that does not deliver output to a printer defines its
queue as a server queue.
Setting Up and Maintaining Queues 14–3