Output priority

JES2 queues a job for output processing when the job completes execution. You can change the default priority assigned to the output by coding the PRTY= keyword on the JCL OUTPUT statement.PRTY= assigns a single priority level between 0 and 255 to all work units within a particular output group. The keyword takes effect if you also specified PRTYOUT=YES on the OUTDEF initialization statement; PRTYOUT=NO is the default.

JES2 creates output groups during output processing or during execution in the case of spin (FREE=CLOSE or SPIN=UNALLOC on the DD statement) data sets. Each output group represents a unit of output work to JES2. JES2 places the output group in the job output element queue in order of output priority. If you did not specify a priority on the JCL OUTPUT statement, JES2 computes a priority for each output group from the tables specified by the PRIORITY= parameter on the OUTPRTY initialization statement.

Also, JES2 uses the RECORD= parameter (for line data), the PAGE=parameter (for page data) or both the RECORD= and PAGE= (for data containing line and page data) with the PRIORITY= parameter to determine the priority of the output. JES2 bases the priority on the total number of print lines, punch cards, or pages in the data set which the output group represents. If the output group represents a data set containing both line and page data, the output priority is the average of the priorities specified by the RECORD= and PAGE= parameters, respectively. The following tables show the default values for the priority calculation:

Table 1. Priority calculation default values: Record
For RECORD:	RECORD	n
RECORD values are estimates of the job output lines and cards	2000 5000 15000 279620 . . . 16777215	1 2 3 4 . . . 9

Table 2. Priority calculation default values: Page
For PAGE:	PAGE	n
PAGE values are estimates of the number of job output pages	50 100 300 16777215 . . . 16777215	1 2 3 4 . . . 9

Table 3. Priority calculation default values: Priority
For PRIORITY:	n	PRIORITY
The n value is determined from the PRIORITY table. The PRIORITY table shown contains the default for the corresponding n values	1 2 3 . . . 9	9 8 7 . . . 1

If the total number of output records (lines or cards) is 2000, then:

From RECORD, 2000 output records indicates n = 1
From PRIORITY, n = 1 indicates PRIORITY = 9

If the total number of output pages is 300, then:

From PAGE, 300 output records indicates n = 3
From PRIORITY, n = 3 indicates PRIORITY = 7

If the total number of output is 2000 lines and 300 pages, then the output priority is the average of both types of output based on the RECORD and PAGE values as follows:

    From RECORD, 2000 output records indicates n = 1
    From PAGE, 300 output records indicates n = 3
    The average value of n = (1 + 3) / 2 = 2
    From PRIORITY, n = 2 indicates PRIORITY = 8

By specifying other values for the tables (during JES2 initialization), you can more closely control your installation's priority assignments. If you do build your own priority table based on estimated record/page counts, be certain that you supply the values in ascending order as the RECORD, PAGE, and PRIORITY(n) values are in the default tables, above. This requirement exists because JES2 uses the RECORD= or PAGE= values in a “less than or equal to” order when calculating a priority that does not exactly match the values in the tables.

JES2 selects output groups for output processing based on the job's output priority. You can cause the priority to increase through the priority aging feature. You can set the original priority on the OUTPRTY(n) statement. However, if the priority is within the limits set by PRTYLOW= (the minimum) and PRTYHIGH= (the maximum), JES2 increases the priority of the job at a rate specified by PRYORATE=. See Output priority aging for additional information about output priority aging.

When a job completes output processing (all of its output groups created and added to the job output element queue), JES2 queues the job for hard-copy.

When assigning such things as priority classes and forms requirements for data sets, you should balance the choices against the criteria JES2 uses to select the output data sets to process.