IOCDS generation options

Edit online
IOCP writes an IOCDS only if:
  • No errors are encountered during IOCP processing.
  • You specify a write IOCDS option WRTAx.
  • The user issuing the IOCP command has the correct privilege class. See Note 3 in IOCP command – usage notes for VM.
  • The IOCDS is not write-protected on the Support Element.
  • You are writing the IOCDS from an authorized logical partition (that is, I/O Configuration Control Authority is enabled for the logical partition on the Support Element).
Use a write option WRTAx after you have:
  • Checked the syntax of the input statements
  • Generated an IOCDS based on the configuration defined in the statements
  • Reviewed reports on the generated IOCDS
  • Checked to see whether the I/O configuration generated by IOCP corresponds to the I/O configuration in the system configuration file (SYSTEM CONFIG) on the parm disk. While IOCP must define the entire I/O configuration, only the devices that VM cannot sense during IPL must be defined in the SYSTEM CONFIG.

If you want to replace an IOCDS that is write-protected, you must also remove the write protection. Use Disable Write Protection under Options on the Input/Output Configuration window of the Support Element to remove write protection.

When IOCP writes the generated IOCDS to the Support Element hard disk, the previous configuration data in that IOCDS is overlaid and lost, even if that IOCDS is the active IOCDS. (The active IOCDS is the one used for the last power-on reset or the last dynamic activation from the system control program (SCP).)
NOWRTCDS
NOWRT
Specifies that IOCP is not to write an IOCDS to the Support Element hard disk. This option is a default.
Use the NOWRTCDS option in either of the following situations:
  • You are checking the syntax of the input file and do not want to write to the Support Element hard disk until you have successfully checked the input file.
  • You are using a CPC that does not require the IOCP that this publication describes.

However, certain CPCs permit an IOCDS to be written in anticipation of supporting ICP IOCP.

When you specify the NOWRTCDS option and IOCP finds no errors, the output file contains the configuration reports of the IOCDS that IOCP generates from your input, along with a list of your input file. If IOCP finds errors, your output file contains only a list of your input file and any errors that IOCP finds.

WRTAx
WAx
Specifies that IOCP is to write the Ax (where x is 0, 1, 2, or 3) IOCDS to the Support Element hard disk. Privilege class C is required to write an IOCDS and privilege class B is required to enable dynamic I/O configuration capability.
Note: An IOCDS can be written only from an authorized logical partition (that is, I/O Configuration Control Authority is enabled).
CHECKCPC
Specifies that IOCP generates an IOCDS as follows:
  • Based on the CPC on which IOCP is running if writing an IOCDS. IOCP ignores the SYSTEM= keyword on the ID statement if specified.
  • Based on the CPC on which IOCP is running if not writing an IOCDS and the SYSTEM= keyword was not specified.
  • Based on the SYSTEM= parameter if specified and IOCP is not writing an IOCDS.
This option is the default.
NOCHKCPC
Specifies that the IOCDS is being written in preparation of a CPC upgrade. IOCP generates an IOCDS based on the SYSTEM= parameter on the ID statement and writes the IOCDS to the current CPC. See Machine rules to determine which CPCs can write an IOCDS with NOCHKCPC and which CPCs can have an IOCDS written to them by ICP IOCP.

The IOCDS cannot be used to power-on reset the current CPC until it is upgraded to the type of CPC supported by the IOCDS. For example, if IOCP generates an IOCDS for an 8561 CPC using SYSTEM=(8561,1) and writes the IOCDS to a general purpose 3906 model, the IOCDS cannot be used for power-on reset until the 3906 is upgraded to an 8561 model CPC.

A WRTAx or WAx option is required. Also, the SYSTEM keyword on the ID statement must be specified.

Attention: Use NOCHKCPC only in preparation of a CPC upgrade. After the upgrade, write an IOCDS using CHECKCPC at your earliest convenience. Doing so precludes the possibility of using the initial IOCDS for a second upgrade to a CPC which does not support the IOCDS and fails power-on reset.