如何判断一个机器的MSSQL是否启动

//判断一个机器的MSSQL是否启动,通过SQL DMO是可以的,但对于没有装MSSQL的客户端来说就没办法,此处用的是连接MSSQL的1433端口,如果端口号不同,可以通过传递端口.
unit Judge_U;

interface
uses
  SysUtils, Classes, IdBaseComponent, IdComponent, IdTCPConnection, IdIcmpClient,
  IdTCPClient, IdRawBase, IdRawClient;

  function JudgePort(AServerName: PChar; APort: Integer): Boolean;
  function JudgePing(AServerName: PChar): Boolean;
implementation

function JudgePing(AServerName: PChar): Boolean;//这个是用来PIN计算机的.
var
  ICMP: TIdIcmpClient;
begin
  ICMP := TIdIcmpClient.Create(nil);
  ICMP.ReceiveTimeout := 1000;
  ICMP.Host := AServerName;
  try
    ICMP.Ping;
    Result := True;
  except
    Result := False;
  end;
  ICMP.Free;   
end;

function JudgePort(AServerName: PChar; APort: Integer): Boolean;
var
  IdTCPClient1: TIdTCPClient;
begin
  IdTCPClient1 := TIdTCPClient.Create(nil);
  IdTCPClient1.Host := AServerName;
  IdTCPClient1.Port := APort;
  try
    IdTCPClient1.Connect;
    Result := True;
    IdTCPClient1.Disconnect;
  except
    Result := False;
  end;
  IdTCPClient1.Free;
end;

end.
//有以下已知的BUG.
  //1  如果一台计算机上安装了多个实例.
  //2  如果不用TCP/ip协议,而用其它的连接方式,比如典型的命名管道,就无法判断.