The best way to always detect a removable device

Question

In my previous question "How to find the unique serial number of a flash device?" I ended up asking for a way to get the drive letter. That problem is solved.

However, my initial question has not been answered. I wanted to be able to tell removable devices (USB drives, SD cards, (external HDDs?), etc.) apart and always be able to recognise them again when they are reconnected. This should also be possible on any other computer. Luckily, I don't care about the drives being formatted (if/when they are, they are treated as new drives in my program), so can I use partition and volume IDs as a part of my recognition? I am asking this as PNPDeviceID is NOT unique. I found that it depends on the hardware reading it, see below pictures:

So, what I am searching for is a way to detect and recognise any removable device on any computer using the following: Win32_DiskDrive, Win32_DiskPartition, Win32_LogicalDisk. I am thanking RRUZ for the original code:

program GetWMI_USBConnectedInfo;

{$APPTYPE CONSOLE}

uses
  Windows,
  Classes,
  ActiveX,
  Variants,
  SysUtils,
  WbemScripting_TLB in '..\..\Documents\RAD Studio\5.0\Imports\WbemScripting_TLB.pas';

procedure  GetUSBDiskDriveInfo;
var
  WMIServices  : ISWbemServices;
  Root,a,b     : ISWbemObjectSet;
  Item,Item2   : Variant;
  i,ii,iii,iiii: Integer;
  start,stop,freq:Int64;
begin
  QueryPerformanceFrequency(freq);
  QueryPerformanceCounter(start);

  WMIServices := CoSWbemLocator.Create.ConnectServer('.', 'root\cimv2','', '', '', '', 0, nil);
  Root := WMIServices.ExecQuery('Select * From Win32_DiskDrive','WQL', 0, nil);
  for i := 0 to Root.Count - 1 do
  begin
    Item := Root.ItemIndex(i);
    for ii := VarArrayLowBound(Item.Capabilities, 1) to VarArrayHighBound(Item.Capabilities, 1) do if (Item.Capabilities[ii] = 7) then begin
      Writeln('Caption      '+VarToStr(Item.Caption));
      Writeln('Name         '+VarToStr(Item.Name));
      Writeln('DeviceID     '+VarToStr(Item.DeviceID));
      Writeln('Partitions   '+VarToStr(Item.Partitions));
      Writeln('PNPDeviceID  '+VarToStr(Item.PNPDeviceID));
      Writeln('SerialNumber '+VarToStr(Item.SerialNumber));
      Writeln('Signature    '+VarToStr(Item.Signature));

      a := WMIServices.ExecQuery('ASSOCIATORS OF {Win32_DiskDrive.DeviceID=''' + VarToStr(Item.DeviceID) + '''} WHERE AssocClass = Win32_DiskDriveToDiskPartition','WQL', 0, nil);
      for iiii := 0 to a.Count - 1 do begin
        b := WMIServices.ExecQuery('ASSOCIATORS OF {Win32_DiskPartition.DeviceID=''' + VarToStr(Variant(a.ItemIndex(iiii)).DeviceID) + '''} WHERE AssocClass = Win32_LogicalDiskToPartition','WQL', 0, nil);
        for iii := 0 to b.Count - 1 do begin
          Item2 := b.ItemIndex(iii);
          Writeln('Drive = ' + Item2.Caption);
        end;
      end;
      Writeln;
      Writeln;
    end;
  end;
  QueryPerformanceCounter(stop);
  if (freq > 0) then
    Writeln('Time took: ' + FloatToStr((stop-start) / freq))
  else
    Writeln('Unable to measure time!');
end;

begin
  try
    CoInitialize(nil);
    GetUSBDiskDriveInfo;
    Readln;
    CoUninitialize;
  except
    on E:Exception do
    Begin
        CoUninitialize;
        Writeln(E.Classname, ': ', E.Message);
        Readln;
    End;
  end;
end.

EDIT
I should add that the code detecting the drives when they are inserted is already working, though it only gives me the drive letter. I use that drive letter to get all the other info from the WMI.

Final edit
I have read that developers can safely use partition/volume ID for recognition. Can I count on that?

Answer 1

You should be able to use the volume id paired with total disk size and volume name to determine if a disk is the same or not, although volume id by itself should be sufficient.

The only problem might be mass produced media. In some instances the volume id, disk size and volume name would match for all copies.

EDIT I'm not sure if you can absolutely get around it for all devices generically. Hardware from each vendor is different, and the specifications are up for interpretation, which is why serial number for some devices is null, for some its not. Your only hope would be to either supply the hardware yourself or to require specific hardware which behaves in a predictable manner.

If you can write to the device, and it would be acceptable to the user, you could create a read only system hidden file containing a unique identifier (such as a guid) and use that file for comparison. This would only stop average users who run windows with the defaults (hide system files, and don't have show hidden files checked) from copying the file, and including the volume id, disk size and volume name also in your check would insist that it is only allowed to a mirrored device. It might not get all instances, but it might get enough.