By default, Avanti retains six serial log files.  If a serial log file is present when Avanti is launched, it is renamed <base>_VirtualAlphaName_serial#.log;-1.  On a subsequent Avanti launch, it would become <base>_VirtualAlphaName_serial#.log;-2, and so on.  The user can increase or decrease the number of serial log files retained using the keep field.