example in control file 202 of fig4 a records are allocated in cell n for the new index table 402 and records in cell p are allocated for the new art 404 the new art 404 is locked and data is copied from the current index table 208 to the new index table 402 and from the current art 214 to the new art 404 step 316 there is no need to lock the index table because the locks on the density map and art protects the index table the updates to the control file concerning the pointer to the index table and the location of the index table are protected by the lock on the density map since the address of the index table may only be found from the pointer in the density map if other applications or processes are queued on the lock of the density map the index table cannot be referenced until the lock is released the lock on the density map is maintained throughout expansion of a freespace file in order to protect the index table the index table can be quite large and is not referenced frequently thus when a pointer to a bit map is needed the corresponding word of the index table is read into memory the in memory pointer to the index table 222 in the in memory density map is protected by the lock on the art references to the index table pointer in memory are made under the protection of the art lock it will be appreciated however that a different locking protocol could be implemented to include locking the index table when updates to it.