Memorex LOCK - VERSION 2-24 Especificaciones descargar pdf (Pagina 246)

ISAM Datasets Types of Datasets

7-26 User Reference

ISAM Datasets

BIM-EPIC can control ISAM datasets. The following VSE restrictions affect ISAM dataset

processing with BIM-EPIC:

• BIM-EPIC can control only one prime data area, one overflow area, and one index per

ISAM dataset.

• ISAM datasets are automatically allocated on cylinder boundaries.

•

If UNCDSK=YES is specified as a configuration option, or if you specify DLBL

options in your JCL, uncontrolled ISAM datasets are limited to a maximum of 5 extents

total.

There are no special requirements for the catalog entry. Extent size specified in the catalog

refers to the prime data area. Multiple extents are not allowed. Extent information for the

index and overflow areas is taken from JCL. The disk pool applies to all areas, prime data,

index, and overflow.

EXTENT statements are always required for all three areas, as follows:

1. For catalog controlled datasets, the number of tracks to allocate for the prime area is taken

from the catalog, unless you specify the DLBL ‘O’ option. The number of tracks to allocate

for index and overflow areas must be specified on the appropriate extent statement, as shown

in the following two examples:

// DLBL MASTER,'EPIC.ISAM.MASTER.FILE',,ISE

// EXTENT SYS040,,4,1 Index

// EXTENT SYS041,,1,2 Prime

// EXTENT SYS042,,2,4 Overflow

// DLBL MASTER, 'EPIC.ISAM.MASTER.FILE',,ISC

// EXTENT SYS040,,4,1,,15 Index

// EXTENT SYS041,,1,2 Prime

// EXTENT SYS042,,2,4,,30 Overflow

2. For Start Track 1, the SYS number for the overflow extent must be different from the SYS

number for the index and prime data areas, as shown in the following example:

// DLBL MASTER,'EPIC.ISAM.MASTER.FILE',,ISE

// EXTENT SYSO4O,POOL80,4,1,1,15 Index

// EXTENT SYS041,POOL80,1,2,1,90 Prime

// EXTENT SYSO42,POOL80,2,3,1,30 Overflow

3. For each DD statements, specify DCB=DSORG=IS or DCB=DSORG=ISU.

The three areas of an ISAM dataset (prime, index, and overflow areas) are all defined as part

of the same DD statement. However, the overflow area must be defined using its own

parameters (DSN, DCB, DISP, SPACE, VOL, and so on). You can define the prime and

index areas together (with one set of parameters) or independently.

Description

DSN Catalog

JCL Requirements

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Memorex LOCK - VERSION 2-24 Especificaciones Pagina 246