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z/OS VSAM and Access Method Services (SS83G)

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Detaillierter Kursinhalt

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


  • 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


  • 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


  • 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


  • 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