2 Responses for "Converting a volume name to a device name"

1. ac April 7th, 2012 at 12:16 1

   “\Device\HarddiskVolume1″

   That’s not a device name. It’s a DOS name for the volume.

   \\.\PHYSICALDRIVE …
   is the name for the device. And I’m not finding too many examples on how to get a list volumes on a physicaldriveX or check what PHYSICALDRIVE a volume is on.

2. ac April 7th, 2012 at 13:00 2

   Here’s the code to get physicaldrive from volumeguid:

   [DllImport("Kernel32.dll", SetLastError = true, CharSet = CharSet.Auto)]
   public static extern SafeFileHandle CreateFile(string fileName, [MarshalAs(UnmanagedType.U4)] FileAccess fileAccess, [MarshalAs(UnmanagedType.U4)] FileShare fileShare, IntPtr securityAttributes, [MarshalAs(UnmanagedType.U4)] FileMode creationDisposition, int flags, IntPtr template);

   [DllImport("kernel32.dll", ExactSpelling = true, SetLastError = true, CharSet = CharSet.Auto)]
   static extern bool DeviceIoControl(Microsoft.Win32.SafeHandles.SafeFileHandle hDevice, uint dwIoControlCode,
   IntPtr lpInBuffer, uint nInBufferSize,
   IntPtr lpOutBuffer, uint nOutBufferSize,
   out uint lpBytesReturned, IntPtr lpOverlapped);

   [DllImport("Kernel32.dll", SetLastError = true)]
   internal static extern bool CloseHandle(IntPtr hObject);

   [StructLayout(LayoutKind.Sequential)]
   internal struct DISK_EXTENT
   {
   internal int DiskNumber;
   internal long StartingOffset;
   internal long ExtentLength;
   }

   public static string GetPhysicalDrive(string volumeid)
   {
   String Result = String.Empty;
   //\\?\Volume{e4d4a1ae-407c-11e1-9f1a-005056c00008}\
   volumeid=volumeid.TrimEnd(‘\\’);
   using (SafeFileHandle device = CreateFile(volumeid, FileAccess.Read, FileShare.Write | FileShare.Read | FileShare.Delete, IntPtr.Zero, FileMode.Open, FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_SEQUENTIAL_SCAN, IntPtr.Zero))
   {
   if (device.IsInvalid) return “”;
   int size = 0×400;//some big size
   IntPtr buffer = Marshal.AllocHGlobal(size);
   uint bytesReturned = 0;

   DeviceIoControl(device, 0×00560000, IntPtr.Zero, 0, buffer, (uint)size, out bytesReturned, IntPtr.Zero);
   // DOES NOT SUPPORT VOLUMES THAT SPAN DIFFERENT DRIVES
   if (bytesReturned > 0)
   {
   int numberOfDiskExtents = (int)Marshal.PtrToStructure(buffer, typeof(int));
   if (numberOfDiskExtents > 1)
   return String.Empty;
   IntPtr extentPtr = new IntPtr(buffer.ToInt32() + Marshal.SizeOf(typeof(long)));
   DISK_EXTENT extent = (DISK_EXTENT)Marshal.PtrToStructure(extentPtr, typeof(DISK_EXTENT));
   Result = String.Format(“\\\\.\\PHYSICALDRIVE{0}”, extent.DiskNumber);
   }
   Marshal.FreeHGlobal(buffer);
   }
   return Result;
   }