What if the win10 hard drive does not recognize?

After Microsoft's push preview version of Win10 Build 9879 was updated, many users reported that the hard disk could not recognize the fault, and many users solved this problem temporarily by installing Intel RST driver and Linux image recovery. However, the solution is not the focus of this article. Below, IT House will explain why Win10 Build 9879 does not recognize the hard disk.
PUIS (Power-up in standby), the hard disk will enter the standby mode, and when the ATA command is received, the rotation is started to achieve maximum energy saving.
Once the hard drive enters the on-demand boot state, the hard drive will no longer respond to the power/hardware/operating system boot request. If you need to re-enable the hard disk, you need to first send the Set Feature command through the ATA standard interface. The command is 0xEF, and then you can call the 0x86 command to turn off the PUIS state. Or call 0x07 to instruct the hard disk to spin start when receiving power supply.

The Windows 10 Preview will open PUIS mode each time it is launched. Need to be reminded that some hard drive manufacturers have blocked this feature and will not be affected by this. IDE mode does not support on-demand booting and will not be affected by this. As for the Linux image, the repair process will turn off the on-demand boot (PUIS) state, and some hard disks may still be affected again after the power is turned off.