JCL UNIT and VOLUME Parameter

The UNIT and VOLUME Parameters are important for properly defining the device type and volume serial numbers of the dataset.

Let us understand UNIT and VOLUME Parameters separately one by one-

1. UNIT Parameter

UNIT Parameter is an optional Keyword parameter which is used to specify the location of the dataset

The Syntax of UNIT Parameter:
UNIT=(device_name,[count])

Here, [count] is optional.

Example 1 - Most Common Example

UNIT=SYSDA

This means that the location of the dataset (on which UNIT=SYSDA is defined) is in DASD(Direct Access Storage Device).

Example 2 - To code a specific UNIT

UNIT=2741

This is used to request the UNIT type on 2741 device. It might be a Tape device.

Note Here, 2741 is a number for 2741 device. Similarly, you can provide any other device type number as well based on your requirement.

Example 3

UNIT=INFILE

This is used to request the UNIT type on INFILE

VOLUME is an optional Keyword parameter which is used to specify the volume serial number where the dataset resides

The Syntax of VOLUME:
VOLUME=(P,R,VS,VC,SER)

P – Private
R – RETAIN
VS – Volume serial number
VC – Volume count
SER – Serial number. This is mandatory if you code VOLUME

Example 1 for VOLUME Parameter

VOLUME=SER=456

As Serial number is mandatory so, you can skip other parameters as shown above.

Example 2 for VOLUME

VOLUME=(,,3,,SER=(LT001,LT002))

In this case, we have not given any value for Private and Retain.

Volume serial number is 3 and there is no value assigned for volume count.

Serial numbers are LT001 and LT002