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While I was trying to find out why the main disk is performing a form of unexpained "thrashing"(while there was no RAM issue), freezing up apps temporarily, I found a relevant error in the logs:

"The driver detected a controller error on \Device\Harddisk1\DR1"

and I'm trying to find which drive it is.

However, from device manager and disk management, the main disk is "0" and there are informational mentions in the logs of dr0 when I enable/disable write caching so it does recognize 0 as different from dr1.

Howevever, the computer has no other disk that I know of and if I open it up while it does have a space for it (laptop), it has no connections for a new one.

I wonder if it's a 'hidden' device of some sort or a problem with the manufacturer's blocking of connections.

In any case I'd like to find out which that device is precisely.

On device manager, DVD drive is mentioned as 'CD ROM 0" when I use 'Populate' in the Volumes tab of its properties and similarly HDD reports disk 0. I still wonder though if for some reason the dvd drive is considered as disk 1 but there's no confirmation of it anywhere. Any other devices such as USB drives etc. are shown as 2, 3, 4 etc. on drive management.

Also looking in HKEY_LOCAL_MACHINE I can only see HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 0\Scsi Bus 0\Target Id 0\Logical Unit Id 0 as PhysicalDrive2 which is a bit weird now that I think of it. That location also confirms the model of the main known drive.

When changing write caching settings \Device\Harddisk0\DR0 is reported on logs (as an information of the change) so \Device\Harddisk0\DR0 is considered by the system different from \Device\Harddisk1\DR1.

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If you open the properties of a drive in device manager, the object path will be listed under "Physical Device Object name" in the details tab. –  billc.cn Jan 19 '13 at 11:55
Could it just be semantics and inconsistency with Microsoft naming convention for devices that is confusing you? disk 0 in some instances will be the first hard drive, while DR1 is the first hard drive in other situations. –  sunk818 Dec 3 at 19:57

2 Answers 2

This "dd" utility worked for me. But it must be run as administrator to include the */Harddisk/DRx mappings!

 dd --list

It provides a report that allows tracing between the various naming schemes and includes the DRn types.


The mappings is not completely obvious but if one assumes that the NT Block Device Objects are listed in order I think the correct drive can be inferred.

If you have unique drive sizes, it is simple since the report directly shows the size for each DRn.

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You can also do this as administrator:


    Microsoft DiskPart version 6.1.7601
    Copyright (C) 1999-2008 Microsoft Corporation.
    On computer: COMPUTERNAME

    DISKPART> list disk

      Disk ###  Status         Size     Free     Dyn  Gpt
      --------  -------------  -------  -------  ---  ---
      Disk 0    Online          476 GB    11 GB
      Disk 1    Online           59 GB      0 B

    DISKPART> sel disk 1

    Disk 1 is now the selected disk.

    DISKPART> list part

      Partition ###  Type              Size     Offset
      -------------  ----------------  -------  -------
    * Partition 1    Primary             59 GB      0 B
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