Unlike magnetic memory used in computer hard and floppy disks, flash memory is an electrically rewritable memory using one of the basic logic gates of the transistor. The NAND-type device stores data in a series of memory cells organized into 528-byte sectors, 16 sectors in a block. Cards are all solid-state with no moving parts and do not require any batteries or power to retain data for an indefinite period. Data is written sequentially by sector and erased by block. This method works well for large blocks of serial data such as digital music on the Diamond Rio music player or digital pictures on the Toshiba PDR camera. The NOR-type memory devices arrange memory cells in parallel and are better suited for random access.