NOR

NOR – Not OR – a type of logic gate used in solid state drives. NOR flash is used to store code in smartphones. NOR is faster to read than NAND flash but slower to write. It is made from FGMOS or FGMOSFETs (Floating Gate Metal Oxide Field Effect Transistors) which are electronic components that can store either a binary 0 or 1. Parallel NOR flash provides random read access at the byte level, enabling a host processor to execute machine-level instructions directly from a NOR chip. This cannot be done with NAND flash. However write operations take longer with NOR; an entire block of cells must be erased in one operation and then the actual desired binary value for a cell written. NOR cells are also larger than NAND cells, meaning NAND chips have higher capacity than NOR chips.