In almost all cases, the event id 11 message is being posted due to hardware problems with either the controller or, more likely, a device that is attached to the controller in question. The hardware problems can be associated with poor cabling, incorrect termination or transfer rate settings, lazy or slow device responses to relinquish the SCSI bus, a faulty device, or, in very rare cases, a poorly written device driver.
for your convinience i have provided the below link How to troubleshoot event ID 9, event ID 11, and event ID 15 error messages
\Device|Harddisk1\DP is the device that controls PARTITION on the disk
\Device|Harddisk1\DR7 repersents disk as RAW PHYSICAL DRIVE
Each disk have one DR device for PHYSICAL DRIVE and one DP device per partition.
You can simply use autogenerated SymbolicLink \Device\HardDiskX\Partition0 for RAW volume, and \Device\HardDiskX\Partition(1,2,3...) for logical partitions if you are writing your own device drivers.
if you need still more indepth detail
IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS can determine
the PhysicalDisk# given a volume handle.