1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:

.....
  hDeviceHandle :=  CreateFile(Drive,GENERIC_ALL,FILE_SHARE_READ or FILE_SHARE_WRITE,nil,OPEN_EXISTING,0,0);
  Drive         :=  pChar('\\.\J:');
  BytesPerSector:=512;
....

function ReadSector(Sector:Integer):pChar;

begin

  if hdevicehandle<>INVALID_HANDLE_VALUE then

    begin

      result  :=  allocmem(BytesPerSector);

      FileSeek(hdevicehandle,Sector*BytesPerSector,0);

      if FileRead(hdevicehandle,result[0],BytesPerSector)<>BytesPerSector then

        raise exception.Create('Read');

    end;

end;

procedure TMainForm.WriteSector(Buffer: PAnsiChar; Sector: Integer);

begin

  if hdevicehandle<>INVALID_HANDLE_VALUE then

    begin

      FileSeek(hdevicehandle,Sector*BytesPerSector,0);

      if FileWrite(hdevicehandle,Buffer[0],BytesPerSector)<>BytesPerSector then

        raise exception.Create('Write');

    end;

end;