The concept involved in the pen drive is that the memory is stored in the form of the array where in the information or the data is stored. The information or the data is stored in the form of the array of transistors. This array of transistors is called as the cells. Each of these cells stores at least one bit of information traditionally. But due to the advancements in the technology the newer versions may even have multi level cells. The data can be stored in more than a bit or specifically only one bit per cell. This is done by the technique of varying the number of electrons that are placed over the floating gate of the cell.
The concept of the flash memory is based on the principle of the Floating Gate Avalanche Injection Metal Oxide Semiconductor or in short referred to as the FAMOS transistor. This is the NMOS transistor. This transistor has an additional conductor that is suspended in between the source/drain terminals and gate. The flash memory comes usually in two types. These is two types are mentioned below: the first one is the NOR flash and the second one being the NAND flash. The names given to the types of the flash memory actually refer to the type of the logic gate that is used in each storage cell.
The flash memory that is used in the pen drive is actually a non volatile memory that is the contents remain intact even if there is a power failure.
