Using VSAM course outline

Using VSAM

Duration: 2 days

Audience: Programmers and Operations Support staff who need to define and control VSAM datasets

Prequisites: Good working knowledge of an editor and JCL

Attendees are encouraged to bring along sample outputs from LISTCAT commands for discussion during the course

Objectives: Top Contents

On successful completion of this course each student will be able to:

* explain the functions of the VSAM dataset organisations
* explain how catalogs are used to record information
* describe how VSAM uses the catalogs to locate the dataset
* describe how VSAM loads, deletes, and inserts records
* write modal commands to control the execution of the IDCAMS program
* write commands which create VSAM datasets efficiently
* write commands which copy, print, modify, and delete VSAM datasets
* explain the meaning of the LISTCAT information
* write statements which will allow VSAM datasets to be accessed by programs
* write commands which create, load, and use Alternate Indexes
* describe how VSAM uses buffer space
* explain how SHAREOPTIONS control access to datasets
* describe how RLS can be used
* explain how DFSMStvs coordinates CICS and batch VSAM updates

Contents: Top Objectives

VSAM overview
Catalogs; clusters; ALIASes; non-VSAM datasets; alternate indexes; paths; Access Method Services and the IDCAMS program; linear datasets, extended format datasets, compression.

VSAM dataset structure
Control intervals; control areas;control information; RBA; how VSAM stores records in an ESDS, RRDS, KSDS; how VSAM retrieves, deletes, and inserts records; control interval splits, control area splits, freespace definition and usage.

Using IDCAMS
JCL needed to run IDCAMS; AMS command syntax; modal commands, IF, DO, END, SET; comments; error messages and return codes.

Defining VSAM datasets
DEFINE CLUSTER command and its parameters; choosing the control interval size; implications for disk space.

Listing Catalog Information
Interpreting LISTCAT output, identifying trouble spots. [Optional: Using other catalog products, such as CBLVCAT, VSAMTUNE.]

Programming with VSAM
Coding requirements for COBOL and PL/1 programs: specifying the file; processing statements; error handling.

Managing VSAM datasets
Loading datasets, copying datasets; printing the contents of clusters; altering cluster parameters; deleting clusters.

Alternate Indexes
Function of an alternate index; how VSAM accesses records using alternate indexes, performance considerations; defining and loading an alternate index; defining a path; JCL and COBOL requirements for alternate indexes.

Performance and data integrity
Functions and performance implications of bufferspace; using multi-volume data sets; record layout, key compression and potential problems; SHAREOPTIONS; expiration dates; Local Shared Resources; Record Level Sharing; DFSMS Transactional VSAM Services, CICS and batch updates.