By using the IOSCDR macro, you can retrieve information that uniquely identifies I/O hardware located along a specific I/O path. For example, you can obtain the model number and serial number, which you can use to uniquely identify a device across multiple systems.
The information that IOSCDR retrieves is returned in an area called a configuration data record (CDR), which is mapped by the mapping macro IHACDR. This CDR, sometimes called the self-description record, is generated by the device's control unit. If you try to obtain these records on devices that do not support self-description and you have specified READ=IO on the IOSCDR macro, you will receive a return code indicating that the device does not support the channel command words (CCWs) needed to generate the records.
The format of the IHACDR is documented in z/OS MVS Data Areas in the z/OS Internet library. For more information about the contents of CDRs, see ESA/390 Common I/O Device Commands.