flash array 32 that is to be sanitized coincide with block boundaries the initial boundary of the first page to be sanitized coincides with the initial boundary of the first block and the final boundary of the last page to be sanitized coincides with the final boundary of the last block but if p sub i gt 0 then the initial boundary of the first page to be sanitized falls between the two boundaries of the first block and the data in pages b sub i 0 through b sub i p sub i u2212 1 must be preserved similarly if p sub f lt p u2212 1 then the final boundary of the last page to be sanitized falls between the boundaries of the last block and the data in pages b sub f p sub f 1 through b sub f p u2212 1 must be preserved therefore if p sub i gt 0 pages b sub i 0 through b sub i p sub i u2212 1 first are copied to a free block 46 similarly if p sub f lt p u2212 1 pages b sub f p sub f 1 through b sub f p u2212 1 first are copied to a free block 46 only then are blocks b sub i through b sub f that span the targeted portion of flash array 32 sanitized most preferably the free block 46 to which pages b sub i 0 through b sub i p sub i u2212 1 are copied is itself sanitized before the pages are copied and the free block 46 to which pages b sub f p sub f 1 through b sub f p u2212 1 are copied is itself sanitized before the pages are copied also most.