How to obtain the physical number of Hard Drive (not a logical number of the Volume)

To capture the Fisical serial number of Hard Disk:

function GetIdeDiskSerialNumber : String;
type
  TSrbIoControl = packed record
     HeaderLength : ULONG;
     Signature    : Array[0..7] of Char;
     Timeout      : ULONG;
     ControlCode  : ULONG;
     ReturnCode   : ULONG;
     Length       : ULONG;
   end;
   SRB_IO_CONTROL = TSrbIoControl;
   PSrbIoControl = ^TSrbIoControl;

   TIDERegs = packed record
     bFeaturesReg     : Byte; // especificar "comandos" SMART
     bSectorCountReg  : Byte; // registro de contador de setor
     bSectorNumberReg : Byte; // registro de número de setores
     bCylLowReg       : Byte; // valor de cilindro (byte mais baixo)
     bCylHighReg      : Byte; // valor de cilindro (byte mais alto)
     bDriveHeadReg    : Byte; // registro de drive/cabeça
     bCommandReg      : Byte; // comando IDE
     bReserved        : Byte; // reservado- tem que ser zero
   end;
   IDEREGS   = TIDERegs;
   PIDERegs  = ^TIDERegs;

   TSendCmdInParams = packed record
     cBufferSize  : DWORD;
     irDriveRegs  : TIDERegs;
     bDriveNumber : Byte;
     bReserved    : Array[0..2] of Byte;
     dwReserved   : Array[0..3] of DWORD;
     bBuffer      : Array[0..0] of Byte;
   end;
   SENDCMDINPARAMS   = TSendCmdInParams;
   PSendCmdInParams  = ^TSendCmdInParams;

   TIdSector = packed record
     wGenConfig                 : Word;
     wNumCyls                   : Word;
     wReserved                  : Word;
     wNumHeads                  : Word;
     wBytesPerTrack             : Word;
     wBytesPerSector            : Word;
     wSectorsPerTrack           : Word;
     wVendorUnique              : Array[0..2] of Word;
     sSerialNumber              : Array[0..19] of Char;
     wBufferType                : Word;
     wBufferSize                : Word;
     wECCSize                   : Word;
     sFirmwareRev               : Array[0..7] of Char;
     sModelNumber               : Array[0..39] of Char;
     wMoreVendorUnique          : Word;
     wDoubleWordIO              : Word;
     wCapabilities              : Word;
     wReserved1                 : Word;
     wPIOTiming                 : Word;
     wDMATiming                 : Word;
     wBS                        : Word;
     wNumCurrentCyls            : Word;
     wNumCurrentHeads           : Word;
     wNumCurrentSectorsPerTrack : Word;
     ulCurrentSectorCapacity    : ULONG;
     wMultSectorStuff           : Word;
     ulTotalAddressableSectors  : ULONG;
     wSingleWordDMA             : Word;
     wMultiWordDMA              : Word;
     bReserved                  : Array[0..127] of Byte;
   end;
   PIdSector = ^TIdSector;

const
   IDE_ID_FUNCTION               = $EC;
   IDENTIFY_BUFFER_SIZE          = 512;
   DFP_RECEIVE_DRIVE_DATA        = $0007c088;
   IOCTL_SCSI_MINIPORT           = $0004d008;
   IOCTL_SCSI_MINIPORT_IDENTIFY  = $001b0501;
   DataSize = sizeof(TSendCmdInParams)-1+IDENTIFY_BUFFER_SIZE;
   BufferSize = SizeOf(SRB_IO_CONTROL)+DataSize;
   W9xBufferSize = IDENTIFY_BUFFER_SIZE+16;
var
   hDevice : THandle;
   cbBytesReturned : DWORD;
   pInData : PSendCmdInParams;
   pOutData : Pointer; // PSendCmdOutParams
   Buffer : Array[0..BufferSize-1] of Byte;
   srbControl : TSrbIoControl absolute Buffer;

procedure ChangeByteOrder( var Data; Size : Integer );
var ptr : PChar;
     i : Integer;
     c : Char;
begin
   ptr := @Data;
   for i := 0 to (Size shr 1)-1 do
   begin
     c := ptr^;
     ptr^ := (ptr+1)^;
     (ptr+1)^ := c;
     Inc(ptr,2);
   end;
end;

begin
   Result := '';
   FillChar(Buffer,BufferSize,#0);
   if Win32Platform=VER_PLATFORM_WIN32_NT then
   // Windows NT, Windows 2000, Windows XP
   begin
   // recuperar handle da porta SCSI
     hDevice := CreateFile('\\.\Scsi0:',
     // Nota: '\\.\C:' precisa de privilégios administrativos
     GENERIC_READ or GENERIC_WRITE,
     FILE_SHARE_READ or FILE_SHARE_WRITE,
     nil, OPEN_EXISTING, 0, 0);

     if hDevice=INVALID_HANDLE_VALUE then Exit;
     try
       srbControl.HeaderLength := SizeOf(SRB_IO_CONTROL);
       System.Move('SCSIDISK',srbControl.Signature,8);
       srbControl.Timeout      := 2;
       srbControl.Length       := DataSize;
       srbControl.ControlCode  := IOCTL_SCSI_MINIPORT_IDENTIFY;
       pInData := PSendCmdInParams(PChar(@Buffer) + SizeOf(SRB_IO_CONTROL));
       pOutData := pInData;
       with pInData^ do
       begin
         cBufferSize  := IDENTIFY_BUFFER_SIZE;
         bDriveNumber := 0;
         with irDriveRegs do
         begin
           bFeaturesReg     := 0;
           bSectorCountReg  := 1;
           bSectorNumberReg := 1;
           bCylLowReg       := 0;
           bCylHighReg      := 0;
           bDriveHeadReg    := $A0;
           bCommandReg      := IDE_ID_FUNCTION;
         end;
       end;

       if not DeviceIoControl( hDevice, IOCTL_SCSI_MINIPORT, @Buffer, BufferSize, @Buffer, BufferSize, cbBytesReturned, nil) then
         Exit;
       finally
         CloseHandle(hDevice);
       end;
     end
   else
     begin
     // Windows 95 OSR2, Windows 98, Windows ME
     hDevice := CreateFile( '\\.\SMARTVSD', 0, 0, nil, CREATE_NEW, 0, 0 );
     if hDevice=INVALID_HANDLE_VALUE then Exit;
     try
       pInData := PSendCmdInParams(@Buffer);
       pOutData := @pInData^.bBuffer;
       with pInData^ do
       begin
         cBufferSize  := IDENTIFY_BUFFER_SIZE;
         bDriveNumber := 0;
         with irDriveRegs do
         begin
           bFeaturesReg     := 0;
           bSectorCountReg  := 1;
           bSectorNumberReg := 1;
           bCylLowReg       := 0;
           bCylHighReg      := 0;
           bDriveHeadReg    := $A0;
           bCommandReg      := IDE_ID_FUNCTION;
         end;
       end;

       if not DeviceIoControl( hDevice, DFP_RECEIVE_DRIVE_DATA,
       pInData, SizeOf(TSendCmdInParams)-1, pOutData, W9xBufferSize, cbBytesReturned, nil ) then
         Exit;
       finally
         CloseHandle(hDevice);
       end;
     end;

     with PIdSector(PChar(pOutData)+16)^ do
     begin
       ChangeByteOrder(sSerialNumber,SizeOf(sSerialNumber));
       SetString(Result,sSerialNumber,SizeOf(sSerialNumber));
     end;
end;



how to call the function:
1) Create this variables:
       s : String;
       rc : DWORD;

2) on onClick of Event of Button, paste this code
     s := GetIdeDiskSerialNumber;
     if s='' then
     begin
       rc := GetLastError;
       if rc=0 then
         showmessage('Drive IDE don´t suport SMART')
       else
         showmessage(SysErrorMessage(rc));
     end
     else
       showmessage('Fisical serial number disk is: ' + s);