Creating a linear data set

To create the data set, you need to specify the DEFINE CLUSTER function of IDCAMS with the LINEAR parameter. When you code the SHAREOPTIONS parameter for DEFINE CLUSTER, the cross-system value must be 3; that is, you may code SHAREOPTIONS as (1,3), (2,3), (3,3), or (4,3). Normally, you should use SHAREOPTIONS (1,3).

When creating a linear data set for data-in-virtual, you can use the LOCVIEW parameter of the DIV macro in conjunction with the other SHAREOPTIONS. LOCVIEW is described under the topic The ACCESS service. For a complete explanation of SHAREOPTIONS, see z/OS DFSMS Using Data Sets.

The following is a sample job that invokes Access Method Services (IDCAMS) to create the linear data set named DIV.SAMPLE on the volume called DIVPAK. When IDCAMS creates the data set, it creates it as an empty data set. Note that there is no RECORDS parameter; linear data sets do not have records.

//JNAME    JOB 'ALLOCATE LINEAR',MSGLEVEL=(1,1),
//         CLASS=R,MSGCLASS=D,USER=JOHNDOE
//*
//*        ALLOCATE A VSAM LINEAR DATASET
//*
//CLUSTPG  EXEC PGM=IDCAMS,REGION=4096K
//SYSPRINT DD SYSOUT=*
//DIVPAK   DD UNIT=3380,VOL=SER=DIVPAK,DISP=OLD
//SYSIN    DD *
           DEFINE CLUSTER (NAME(DIV.SAMPLE) -
                  VOLUMES(DIVPAK) -
                  TRACKS(1,1) -
                  SHAREOPTIONS(1,3) -
                  LINEAR)
/*

For further information on creating linear VSAM data sets and altering entry-sequenced VSAM data sets, see z/OS DFSMS Access Method Services Commands.