Abstract: A method of allocating free physical memory in a solid state memory disk for a sector of data of a given size is described. Allocation begins by determining whether sufficient free memory remains in the block to which the previous sector of data was written. If there is not sufficient free memory remaining, then selection of another block to allocate the sector of data begins. The selection is based on the sum of the amount of free memory in a selected block and one of the following: 1) the amount of invalid data in the block; 2) the cycle count for the block; 3) the amount of invalid data as compared to a maximum amount of invalid data for all non-volatile memory devices associated with the block; and 4) the number of blocks already allocated to all non-volatile memory devices associated with the block. Afterward, the block with the greatest amount of available memory is selected to store the sector of data.