z/VM: CP Commands and Utilities Reference - z/VM - IBM

Usage Notes
DASD
tells CP that this device is a direct access storage device (DASD).
NOPREFerred_channel_path
tells CP that there is no preferred channel path.
DEFINE DEVICE / IODEVICE
PREFerred_channel_path nn
tells CP to use this channel path to initiate I/O requests before trying any other
channel paths from the device that you are defining. The variable nn must be a
1- to 2-digit hexadecimal number between X'00' and X'FF'.
Note: A preferred path must not be specified for a device connected to a
control unit for which z/OS–managed paths are being used. Although the
command will not prevent you from doing so, the use of preferred paths
in a managed-path environment will adversely affect z/OS’s ability to
manage channel-path workloads.
NOSTATus_verification
tells CP that the status verification facility is not active for this device, and so
the channel subsystem will not check the device’s status.
STATus_verification
tells CP that the status verification facility is active for this device, causing the
channel subsystem to check the device’s status every time this device
announces its status.
NOTIME_Out
tells CP that the I/O interface time out function is not active. This parameter
should not be specified if the device is being defined on a CHPID with
TYPE=BYTE.
TIME_Out
tells CP that the I/O interface time out function is active for the following I/O
interfaces between the channel and I/O device:
v 4 second time out for initial selection
v 30 second time out for data transfer.
SENSed
tells CP to use the information returned from a sense ID request to determine
the device class or type at device initialization.
NOTSENSed
tells CP not to use the information returned from a sense ID request to
determine the device class or type at device initialization.
PARtition pname
specifies the name(s) of the logical partition(s) which will have access to the
device(s) being defined in the specified or implied channel-subsystem image.
The maximum number of logical partition names you can specify depends on
the capabilities of your processor. Each pname must be a 1- to 8-character
alphanumeric string.
Note: When defining CTC devices, only specify a PARTition list that includes
partitions in which they will be used. If ″extra″ partitions are specified,
then the CTC subchannels defined for those extra partitions
unnecessarily use Hardware System Area (HSA) storage.
1. Devices attached to your system communicate with the system through control
units and channel paths. Thus, before you dynamically define a new device to
Chapter 2. CP Commands 157