It kind of answers your question since it is repported safe and replace hardware scan. It need access to the HDD to do the HW scan on the drive. 
I'm getting a protected memory access blocked when Dell.TechHub.Instrumentation.SubAgent.exe tries to access \Device\Harddisk0\DR0. Does anyone from Dell confirm that Dell.TechHub.Instrumentation.SubAgent.exe is not a trojan, explain what it does, and why I should give it access to the hard disk. TIA.
Dell.TechHub.Instrumentation.SubAgent.exe