Tech – Mainframe

Posts related to the mainframe world

FAQ
JES

JES2 Start Methods

13th November 2010 Rui Miguel Feio
The following are the three possible JES2 start methods: 1. WARM – This is the default start method. – WARM specifies that JES2 is to continue processing jobs from where they were stopped. – If the FORMAT option was also coded, then JES2 will ignore the WARM specification and perform […]
FAQ
JES

Job Processing Phases in JES2

3rd November 2010 Rui Miguel Feio
Work to be processed by a z/OS system has to be defined using Job Control Language (JCL). JCL is used to define which program to execute, which resources to allocate, whom to notify, and so forth. This description of work is called a job. z/OS uses a Job Entry Subsystem […]
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JES

What does a JES initiator do?

1st November 2010 Rui Miguel Feio
A JES initiator performs several functions to ensure that multiple jobs run at the same time, without conflicts. To run multiple jobs asynchronously, the system must perform a number of functions: –    Select jobs from the input queues (JES does this). –    Ensure that multiple jobs (including TSO users and […]
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MVS

How to compress LLA-managed libraries

30th October 2010 Rui Miguel Feio
Sometimes a PDS library needs to be compressed to reclaim the free space caused by member deletions. The recommended procedure for compressing an LLA-managed library is: 1. Create a new CSVLLAxx member that includes a REMOVE statement identifying the library that needs to be compressed (ex: CSVLLA02). REMOVE(SYS1.EXAMPLE.FILE) 2. Then […]
JCL

Using IEBCOPY to compress a Data Set

30th October 2010 Rui Miguel Feio
Here’s an example of a IEBCOPY job to compress a data set: //COMPRESS JOB (),’RMF’,NOTIFY=&SYSUID,CLASS=A,MSGLEVEL=(1,1), // MSGCLASS=X //******************************************* //* //* COMPRESS A DATA SET USING IEBCOPY //* //******************************************* //STEP1 EXEC PGM=IEBCOPY //SYSPRINT DD SYSOUT=* //INPUT DD DSNAME=SYS1.EXAMPLE.FILE,DISP=SHR //OUTPUT DD DSNAME=SYS1.EXAMPLE.FILE,DISP=SHR //SYSIN DD * COPY INDD=INPUT,OUTDD=OUTPUT /* Note that we are […]