Creating Utility

  • An access method represents the process that is used to store and retrieve data from the datasets or files.
  • Access Method Services (AMS) is a utility mainly used to define and handle VSAM datasets and integrated catalogs.
  • IDCAMS(Integrated Data Cluster Access Method Services) is the utility program name for access method services (AMS) and used to create the VSAM datasets.
  • The functions of AMS are performed through the different functional commands of IDCAMS.

Syntax -

//JOBNAME  JOB job-card-parameters
//SYSIN    DD *
  AMS commands and their parameters

The below are AMS commands of IDCAMS -

AMS Command Description
DEFINE Creates catalogs and catalog entries for files, alternate indexes, paths, and VSAM data spaces.
ALTER Alters the existing catalog entries.
LISTCAT Lists catalog entries.
PRINT Prints VSAM and nonVSAM files.
REPRO Copies files.
EXPORT Creates a copy of a file for backup or makes a file or user catalog portable to use in another system.
IMPORT Reads a backup copy of a file or makes a file or user catalog previously exported available in another system.
VERIFY Provoke a catalog to correctly reflect the end of a file.
DELETE Deletes catalog entries.

Guidelines for coding commands in IDCAMS -

  • At least one blank space must be between the command, the object, and sub-parameter values.
  • Sub parameter values can be separated using a space or a comma.
  • Space is optional between a parameter and the parenthesis enclosing its values.
  • A hyphen (-) is used to specify the current line extended to the following line.

IDCAMS utility is explained in utilities section .