Data set characteristics

You can define data set characteristics when you allocate a data set or view the characteristics of an existing data set in the data set Properties view.

The following list includes some of the data set characteristics that you can set when you allocate a data set or view in the Properties view when you select a data set name. In the Properties view, these characteristics are read-only. You cannot set values for them in this view. Not all of these characteristics are displayed in the Properties view. If System Managed Storage attributes are not available for a data set, the Properties view displays **NONE** for those attributes.

Volume serial: The volume serial number (VOLUME) for the storage space on DASD on which to allocate the data set.

Generic unit: The generic unit name for the device type.

Space units: Defines the unit of primary and secondary space to be allocated. The default value is BLOCK. Select one of these values:

TRACK: A track of a direct access storage device (DASD).

BLOCK: A block of a DASD.

CYLINDER: A cylinder of a DASD.

Primary quantity: The amount of DASD space to be used for primary space allocation (PRIMARY). The range depends on the space unit specified and the type of DASD. The default value is 300.

Secondary quantity: The amount of DASD space to be used for secondary space allocation (SECONDARY). The range depends on the space unit that is specified and the type of DASD. The default value is 100.

Extents: The number of contiguous tracks, cylinders, or blocks for primary and secondary space allocation. Reading or writing contiguous tracks is faster than reading or writing data that is scattered over the disk.

Directory blocks: Specify the number of directory blocks to allocate. The default value is 20.

Record format: Choose a record format (RECFM) from the list. For more information about data set record formats, see the related topics.

Record length: Specify a logical record size (LRECL) for fixed record formats or a maximum logical record size for variable record formats. Unformatted records have no logical record size.

Block size: Specify the physical block size (BLKSIZE) that is written on the disk for F and FB records. For V, VB, and U records, this value is the maximum physical block size that can be used for the data set.

Data set type: Choose one of the following types (DSNTYPE): LIBRARY(PDSE), LIBRARY(PDSEv2), partitioned data set (PDS), or sequential data set (SEQ).

Number of generations: For a PDSE version 2 library, specify the number of member generations to retain (MAXGENS). When the number of member generations exceeds this value, older generations are discarded. The default value is 0.

DSORG: Data set organization, such as physical sequential (PS), partitioned (PO), or direct access (DA).

Expiration date: You can specify a date on which the data set is automatically deleted. Use this format: YYYYDDD. 2015012, for example, is January 12, 2015.

Extended attribute: Specify whether the data set can support extended attributes (format 8 and 9 DSCBs). To create such data sets, you can include extended address volumes (EAVs) in specific storage groups, specify an EAV on the request, or direct the allocation to an esoteric containing EAV devices. Specify one of these values:
  • no value: The system's default value.
  • NO: No extended attributes are available. The data set cannot have extended attributes (format 8 and 9 DSCBs) or reside in EAS.
  • OPT: Extended attributes are optional. The data set can have extended attributes and reside in EAS.

System Managed Storage: The information you must provide in this field depends on your business rules and procedures. Your systems administrator can inform you whether you must click System Managed Storage (SMS) to assign a data set to a particular class.

Data class: Name of a data class that is defined in your System Managed Storage (SMS) installation. Do not enter a value on a system without SMS.

Storage class: Name of a storage class that is defined in your System Managed Storage (SMS) installation. Do not enter a value on a system without SMS.

Management class: Name of a management class that is defined in your System Managed Storage (SMS) installation. Do not enter a value on a system without SMS.