Schulung - IBM SS83G - z/OS VSAM and Access Method Services

Course Outline

Introduction to VSAM data sets

• describe the structure, organization, and use of VSAM clusters
• explain the function of Control Intervals (CI) and Control Areas (CA)
• describe the purpose of CI splits and CA splits and how they are accomplished
• estimate DASD space requirements for various cluster types

ICF catalogs

• discuss the use of the ICF catalog
• describe the structure, purpose, and basic contents of the master catalog
• describe how the master catalog is located at initial program load (IPL) time
• discuss the structure, purpose, and basic contents of user catalogs
• create the ICF catalogs
• describe the catalog search
• discuss and create the two types of alias

IDCAMS commands, part 1

• discuss the IDCAMS program
• code the JCL to run IDCAMS
• code the DEFINE CLUSTER command to create specific VSAM data set organizations
• code the LISTCAT command to format and print entries from the catalog

JCL for VSAM

• explain creation and deletion of VSAM clusters using JCL and the DFSMS data class facility
• describe the additional JCL parameters that support VSAM clusters
• discuss the purpose of data class
• explain the assignment of data class through JCL and the Automatic Class Selection (ACS) routines

IDCAMS commands, part 2

• describe the function of REPRO, PRINT and DELETE commands
• use REPRO to load and back up a VSAM cluster
• use PRINT to print a VSAM cluster in various formats
• use DELETE to remove the catalog entry for the data set and scratch the data set from the volume
• describe and code modal commands to provide for conditional execution of Access Method Services (AMS) statements

Buffering

• explain how buffer space may impact performance either positively or negatively
• explain the use of data and index buffers in sequential processing and direct processing
• evaluate the use of JCL Access Method Parameters (AMP) keywords to manage buffers
• code the buffer keywords on the Dataset Definition (DD) statement

VSAM integrity and security

• explain how integrity and security is maintained
• discuss the meaning and use of SHAREOPTIONS
• discuss the need for serialization of updates to a data set
• describe how ENQ/DEQ macros are used to serialize data set updates in multiregion and multisystem environments
• explain the impact of buffering and SHAREOPTION modifications
• explain VSAM record level sharing
• use the VSAM integrity and security options: RECOVERY, ERASE, VERIFY, and passwords
• compare VSAM passwords with Resource Access Control Facility (RACF) security

Tuning

• explain the use of CI and CA FREESPACE
• discuss the performance impact of cache
• describe the space allocation process with KEYRANGES and multivolume data sets
• explain the contents of an Index CI
• explain how VSAM key compression works

IDCAMS ALTER

• explain the basic functions of the ALTER command
• code the ALTER command to modify options for processing existing VSAM objects
• code the ALTER command to modify options for buffering, FREESPACE, SHAREOPTIONS and passwords

Alternate indexes

• describe the reasons for using an alternate index
• discuss the basic contents of an alternate index
• use a PATH to process base cluster records directly and in alternate key sequence
• define and load an alternate index
• explain the impact of SHAREOPTIONS when opening a base cluster and associated alternate indices
• explain programming and JCL considerations

Advanced functions and extended format data sets

• explain VSAM advanced functions, extended format data sets, and their major features
• explain data stripping
• explain compression
• explain multivolume allocation options
• explain extended addressability
• explain system managed buffering
• explain partial space release
• explain space constraint relief

Data set reorganization, backup, and recovery

• describe the need for data set backup
• explain the advantages and disadvantages of REPRO
• explain the advantages and disadvantages of EXPORT / IMPORT
• explain the advantages and disadvantages of DFSMS Data Set Services (DFSMSdss) DUMP / RESTORE
• explain the advantages and disadvantages of DFSMS Hierarchical Storage Management (DFSMShsm) HBACKDS / HRECOVER
• discuss backup frequency
• determine when reorganization is required
• code the AMS commands for backup, recovery, and reorganization

Linear Data Sets (LDS)

• describe Data-In-Virtual (DIV)
• explain the structure and use of LDS
• explain the use of the DIV macro to access LDS
• discuss candidates for LDS

Management and problem analysis aids

• explain the use of the DCOLLECT command to gather management and planning information about the storage subsystem
• discuss tools used to identify and trace VSAM errors
• code the AMS EXAMINE command to test the structure of a Key Sequenced Data Set (KSDS)
• interpret EXAMINE output to determine how to recover from a KSDS structural error
• invoke the Generalized Trace Facility (GTF) to track VSAM-related events
• invoke utilities to print GTF trace output

Local and global shared resources

• explain techniques to conserve virtual storage by sharing buffers and control blocks
• discuss the concept of shared resource pools
• discuss the advantages and disadvantages of Local Shared Resources (LSR)
• discuss the advantages and disadvantages of Global Shared Resources (GSR)
• describe macros that control use and allocation of shared resources
• discuss how to specify and monitor shared buffer allocation in CICS and Information Management System (IMS)

CICS VSAM recovery

• describe the major functions of CICS VSAM recovery
• explain the concept of transaction processing, backup, and recovery
• explain how to implement and manage CICS VSAM recovery

Application coding considerations

• describe VSAM processing terminology
• define various VSAM processing options
• explain the merge of catalog entries, JCL parameters, and program definitions that determine processing options
• discuss VSAM programming support, and JCL requirements in Common Business Oriented Language (COBOL), Programming Language One (PL/I), and Assembler languages
• describe JCL and programming requirements for COBOL, PL/I, and Assembler languages

Objective

• Understand the structure and use of VSAM data sets or clusters
• Code IDCAMS commands to define and load VSAM clusters
• Code IDCAMS commands to define and load alternate indexes
• Code IDCAMS commands to list, alter, and delete catalog entries
• Code IDCAMS commands to print data sets
• Calculate the Direct Access Storage Device (DASD) space requirements for VSAM clusters
• Code the Job Control Language (JCL) for IDCAMS and programs which process VSAM clusters
• Use IDCAMS and JCL options to improve the performance of a VSAM job
• Reorganize, back up, and recover VSAM and non-VSAM data sets
• Interpret an IDCAMS listing of an Integrated Catalog Facility (ICF) catalog
• Select and use the appropriate documentation to utilize VSAM and IDCAMS