The musicians and management of the Chicago Symphony Orchestra have agreed to extend the musicians’ current contract through October 31, and are bringing in a retired judge to mediate further negotiations. The extension will insure that the CSO season will run for at least six weeks without interruption by strike or lockout, and the joint selection of a mediator suggests that, while the talks remain contentious, there is at least a desire on both sides to avoid the public relations disaster that a work stoppage would likely precipitate.