Specifying IOCP statements

Edit online

The rules for coding IOCP card-image statements follow the rules for assembly language. See Coding IOCP statements for a summary of the rules for coding statements and the notation used in this document to illustrate statements.

IOCP has seven statements: ID, RESOURCE, UUID, CHPID, CNTLUNIT, IODEVICE, and FUNCTION. The ID statement is optional; code it if you want specific identification information in the heading of IOCP configuration reports and on Support Element (SE) displays. The RESOURCE statement is required and defines the logical partitions and logical channel subsystems in your configuration. The UUID statement is optional; code it if you want to enable UUID checking for functions in a logical partition. CHPID, CNTLUNIT, IODEVICE, and FUNCTION statements are optional. CHPID defines channel paths, CNTLUNIT defines control units, and IODEVICE defines I/O devices in your configuration. FUNCTION defines the function an adapter will perform in your configuration for some adapters that do not require a channel path.

Note: While IOCP requires only the RESOURCE statement, most I/O configurations need CHPID, CNTLUNIT, and IODEVICE statements to be usable.
The following general rules apply to the sequence of IOCP statements in the input file:
  • You can code the ID statement only once, and it must precede other IOCP statements.
  • You can code the RESOURCE statement only once, and it must precede all CHPID, FUNCTION, and UUID statements.
  • You can code the UUID statement only once, and it must precede all FUNCTION statements.
  • A CHPID statement that defines a channel path must precede a CNTLUNIT statement that refers to the channel path.
  • A CNTLUNIT statement must follow the CHPID statement that defines the channel path to which the control unit is attached.
  • An IODEVICE statement must follow the CNTLUNIT statement that defines the control unit to which the device is assigned.
  • You can insert IOCP comment cards (specified by an asterisk (*) in column 1 or by .* in columns 1 and 2) or blank lines in the input file where you want them.

Because of these rules, it is suggested that you group all CHPID statements, followed by all CNTLUNIT statements, and then all IODEVICE statements. Alternatively, you might group all CHPID statements, followed by groups of related CNTLUNIT and IODEVICE statements (as shown in Lists of statement input).