Why can KillDisk (or hard drive monitor) not return serial numbers from drives hooked up to RAID controllers?

The software uses standard SCSI/ATI function calls (through Windows) to get serial numbers from hard drives.

Most, if not all, RAID controllers do not properly process these requests.

Typically, a RAID controller is used to hook up 2 or more hard drives in such a way that the operating system thinks it is one drive. Therefore, the operating system can not access the drives individually.

When queried for a hard drive's serial number, the RAID controller does not know which serial number to return, so it does not return a serial number at all. All RAID controllers tested will do this even if there is only one drive in the RAID set.