def rescan(self, __hosts, __bus, __target, __lun):
        """ Rescan SCSI
        invokes a rescan via /sys/class/scsi_host/hostH/scan interface
        IDEAS
        INPUTS
          * host - name of scsi host ( - for all )
          * bus - number of scsi bus (- for all )
          * target - number of target ( - for all )
          * lun - number of lun ( - for all )

        """
        __syspath = "/sys/class/scsi_host"

        if not os.path.isdir( __syspath ):
            raise ComException(__syspath + " not found")
    
        if __hosts == "-":
            __hosts=self.getAllSCSIHosts()

        if  not ( ComUtils.isInt(__bus) or  __bus == "-"):
            raise ComException( __bus + " is not valid to scan SCSI Bus"); 
    
        if  not ( ComUtils.isInt(__target) or  __target == "-"):
            raise ComException( __bus + " is not valid to scan SCSI Target")

        if  not (ComUtils.isInt(__lun) or  __lun == "-"):
            raise ComException( __bus + " is not valid to scan SCSI Lun")

        print "Hosts: ", __hosts

        for __host in __hosts:
            ComSystem.execLocal( "echo \""+__bus+"\" \""+ __target+"\" \""+ __lun+ "\" > "+__syspath+"/"+__host+"/scan")
    def rescan(self, __hosts, __bus, __target, __lun):
        """ Rescan SCSI
        invokes a rescan via /sys/class/scsi_host/hostH/scan interface
        IDEAS
        INPUTS
          * host - name of scsi host ( - for all )
          * bus - number of scsi bus (- for all )
          * target - number of target ( - for all )
          * lun - number of lun ( - for all )

        """
        __syspath = "/sys/class/scsi_host"

        if not os.path.isdir(__syspath):
            raise ComException(__syspath + " not found")

        if __hosts == "-":
            __hosts = self.getAllSCSIHosts()

        if not (ComUtils.isInt(__bus) or __bus == "-"):
            raise ComException(__bus + " is not valid to scan SCSI Bus")

        if not (ComUtils.isInt(__target) or __target == "-"):
            raise ComException(__bus + " is not valid to scan SCSI Target")

        if not (ComUtils.isInt(__lun) or __lun == "-"):
            raise ComException(__bus + " is not valid to scan SCSI Lun")

        print "Hosts: ", __hosts

        for __host in __hosts:
            ComSystem.execLocal(
                'echo "' + __bus + '" "' + __target + '" "' + __lun + '" > ' + __syspath + "/" + __host + "/scan"
            )