 For NAND memory, reading and programming are page-wise, and unlocking and erasing are block-wise.Reading from NOR flash is similar to reading from random-access memory, provided the address and data bus are mapped correctly.Because of this, most microprocessors can use NOR flash memory as execute in place (XIP) memory, meaning that programs stored in NOR flash can be executed directly from the NOR flash without needing to be copied into RAM first.