Using the ACS Language and Variables

ACS routines use a simple, procedure-oriented language. ACS routines begin with a PROC statement that identifies the type of ACS routine, such as storage class ACS routine, and terminates with an END statement. Variables that are generated from the allocation environment for the data, such as data set name and job accounting information, are supplied to your routines as ACS read-only variables. You can use these variables to assign a class or group to a data set. This is done by assigning the corresponding read/write variable in your ACS routine. Each routine sets only its own read/write variable, as follows:

The data class ACS routine sets &DATACLAS
The storage class ACS routine sets &STORCLAS
The management class ACS routine sets &MGMTCLAS
The storage group ACS routine sets &STORGRP

The ACS language consists of the following statement types:

DO/END: Use this to define a set of actions that should be run in sequence. Typical use is to assign a class or group to the data set and exit the ACS routine.
EXIT: Enables you to stop processing your ACS routine. You can assign a non-zero return code, using the EXIT statement, to stop allocation.
FILTLIST: Lets you assign a variable to a set of literals or masks. The system uses these variables, defined by filter lists, in comparisons with ACS variables associated with the data set allocation to help assign classes and groups.
IF/THEN: Enables you to compare ACS variables with your own variables created using FILTLIST statements to help assign classes and groups.
SELECT/WHEN: Lets you test variables and run a set of actions logically enclosed by DO and END statements.
SET: Enables you to assign a class or group.
WRITE: You can format messages for users requesting the data set allocation. You can display text or any read-only or read/write variable.

Read-only variables provided to your ACS routines are dependent on the allocation environment. All variables are available for new allocations. However, DFSMSdss CONVERTV, DFSMSrmm RMMVRS or RMMPOOL, and DFSMShsm RECALL or RECOVER environments have a subset of read-only variables. Also, the storage group ACS routine has a restricted set of read-only variables available. z/OS DFSMSdfp Storage Administration describes the read-only variables and the ACS language.