2816	 Optimal Reorganization of Distributed Space Disk Files	 In most database organizations the cost of accessing the database will increase due to structural changes caused by updates and insertions. By reorganizing the database the access costs can be reduced. A basic problem is to establish the proper tradeoff between performance storage costs and reorganization costs. This paper considers the optimum points at which to reorganize a database. A disk file organization which allows for distributed free space is described. A cost function describing the excess costs due to physical disorganization is defined and this function is minimized to obtain the optimum reorganization points. Numerical examples based on the characteristics of existing disk storage devices are given. disk file free space retrieval insertion deterioration reorganization
