Device attributes

Some attributes are common to all devices in a device category, other attributes are specific to a particular device driver. The following attributes are common to all CCW devices:

online

You use this attribute to set the device online or offline. To set a device online, write the value 1 to its online attribute. To set a device offline, write the value 0 to its online attribute.

cutype

specifies the control unit type and model, if applicable. This attribute is read-only.

cmb_enable

enables I/O data collection for the device.

devtype

specifies the device type and model, if applicable. This attribute is read-only.

availability

indicates whether the device can be used. The following values are possible:

good

This is the normal state. The device can be used.

boxed

DASD only: The device is locked by another operating system instance and cannot be used until the lock is surrendered or the DASD is accessed by force.

no device

Applies to disconnected devices only. The device disappears after a machine check and the device driver requests to keep the device online anyway. Changes back to good when the device returns after another machine check and the device driver accepts the device back.

no path

Applies to disconnected devices only. After a machine check or a logical vary off, no path remains to the device. However, the device driver keeps the device online. Changes back to good when the path returns after another machine check or logical vary on and the device driver accepts the device back.

modalias

contains the module alias for the device. It is of the format:

ccw:t<cu_type>m<cu_model>

or

ccw:t<cu_type>m<cu_model>dt<dev_type>dm<dev_model>