Abstract for JES2 Initialization and Tuning Guide · How to send your comments to IBM · Summary How to initialize JES2 in a multi-access SPOOL configuration. JES2 Initialization and Tuning Guide. z/OS JES2 Initialization and Tuning Guide contains the following information in support of JES2 Email Delivery Services. JES2 initialization statement and parameter summary tables · JES2 initialization statement descriptions · APPL(jxxxxxxx) – Application Characteristics.

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Those paper towels on that roll in the kitchen are queued up waiting for you to use each one in turn, just initializatiion a report waiting to be printed or a set of JCL statements initializattion for its turn to run. This data should be compared for all systems to establish which member has the most activity. From the perspective of a single member in a complex, checkpoint-related useful time is the time jse2 a checkpoint cycle, which starts at the beginning of the primary write and ends at the beginning of the final write.

Releases the hardware reserve. The checkpoint mechanism is as follows: Start high, and then lower it if there are problems and you do not see the messages when you wanted to.

There is a lock table in the coupling facility structure associated with a serialized list. This round-robin approach might break when the number of JES2 members increase.

“OS/ V2R JES2 Initialization and Tuning Guide” IBM Library Server

JES2 acquires, uses, and frees the checkpoint on a time slice basis which is set initializaton the installation. On high use systems, the ejs2 of initiators can be reduced while more are started on low use systems.


If the HOLD parameter is set lower than the time it takes for the primary write to 2 JES2 Performance and Availability Considerations complete, the hold time is extended until the primary write completes. An external writer is a program that reads and processes sysout files, and such a program can route the output to any available destination.

Bottlenecks, it might be said. JES2 uses more processor cycles. Often, it is the total number initizlization trace entries written that highlights the problem. Jobs take longer to run. JES2 attempts to maximize the performance of spooling operations, which ultimately benefits the throughput of work through the JES2 installation.

JES2 Initialization and Tuning Guide

This command has significant overhead because of the number of messages that can be issued and the console flooding that can jess2. Free time The free time is the amount of time when no member is using or obtaining the checkpoint. Example 3 shows an example of the output of this command.

You only need to serialize on the checkpoint if you modify the content of one of the queues. There are virtual devices.

It also discusses performance tools that are available for analyzing performance-related data. Each such system has a copy of JES2 running. The following paragraph does not apply to the United Kingdom or any other country where such provisions are inconsistent with local law: Abbreviated forms of these titles are used throughout this document.

CHANGES Summary of changes

Some small development company might have just one job class for everything. However, it is the user’s responsibility to evaluate and verify the operation of any non-IBM product, program, or service. Only low-usage initiallization sets if any should be allocated on the same volume as the checkpoint data set.


Winter Spring Checkpoint Dates. IBM, therefore, cannot guarantee or imply reliability, serviceability, or function of these programs.

As the checkpoint data set is frequently referenced, particularly in MAS configurations, it should not reside on any volume that contains high-usage data sets. This paper concentrates on this method of checkpoint access. Questions on the ahd of non-IBM products should be addressed to the suppliers of those products. So, you can run them with confidence. Compared to disks — even the slower disks used decades ago — the card readers and line printers were ugide slow.

To do so, you can use the following command: This evaluation is done every 10 seconds. Every tenth intermediate write is also written to the down-level DASD data set.

Red books JES2 Performance and Availability Considerations

The number of active JES2 processes and frequency of the following: In this instance, WLM takes no action on the image in question. This is obviously especially necessary when spool sharing is in use. There are real physical devices few card readers, but many variations of printers and vaguely printer-like devices.