# File lib/windows/sys/uptime.rb, line 25
    def self.boot_time(host = Socket.gethostname)
      cs = "winmgmts://#{host}/root/cimv2"
      begin
        wmi = WIN32OLE.connect(cs)
      rescue WIN32OLERuntimeError => e
        raise Error, e
      else
        query = "select LastBootupTime from Win32_OperatingSystem"
        results = wmi.ExecQuery(query)
        results.each{ |ole|
          time_array = parse_ms_date(ole.LastBootupTime)
          return Time.mktime(*time_array)
        }
      end
    end