Speaking of the rumor mill, here's one that actually has some credibility: John Walker, the chief financial officer of the city school system, is resigning. Walker has been rumored to be leaving several times before, but this time he's announced his impending departure to his staff. It's not clear yet when he's going, but assuming it's sometime before the spring, this could leave the system in a tough spot in preparing the budget for next year. The school board tonight is scheduled to commit to an aggressive agenda to complete the budget process much earlier than in years past.