if(Debug.freespace){
_fmChecker.start(0);
}
if(_freespaceManager.requiresMigration(configImpl().freespaceSystem(), _systemData.freespaceSystem())){
FreespaceManager oldFreespaceManager = _freespaceManager;
_freespaceManager = FreespaceManager.createNew(this, _systemData.freespaceSystem());
_freespaceManager.start(newFreespaceSlot(_systemData.freespaceSystem()));
FreespaceManager.migrate(oldFreespaceManager, _freespaceManager);
_fileHeader.writeVariablePart(this, 1);
}