Creating a Windows Service in Delphi

unit diskmon;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls,
SvcMgr, Dialogs,
  ExtCtrls;

type
  TService1 = class(TService)
    Timer1: TTimer;
    procedure Timer1Timer(Sender: TObject);
    procedure ServiceExecute(Sender: TService);
  private
    { Private declarations }
  public
    function GetServiceController: TServiceController; override;
    { Public declarations }
  end;

var
  Service1: TService1;

implementation

{$R *.DFM}

procedure ServiceController(CtrlCode: DWord); stdcall;
begin
  Service1.Controller(CtrlCode);
end;

function TService1.GetServiceController: TServiceController;
begin
  Result := ServiceController;
end;

procedure TService1.Timer1Timer(Sender: TObject);
const
FileName = 'c:\logdate.txt';
var
F: TextFile;
begin
AssignFile(f,FileName);
if FileExists(FileName) then Append(f)
else
Rewrite(f);
writeln(f,DateTimeToStr(Now));
ShowMessage(DateTimeToStr(Now));
CloseFile(f); 
end;

procedure TService1.ServiceExecute(Sender: TService);
begin
Timer1.Enabled := True;
while not Terminated do
ServiceThread.ProcessRequests(True);// wait for termination
Timer1.Enabled := False;
end;

end.