 A string is a series of connected NAND cells in which the source of one cell is connected to the drain of the next one.Depending on the NAND technology, a string typically consists of 32 to 128 NAND cells.Strings are organised into pages which are then organised into blocks in which each string is connected to a separate line called a bitline (BL) All cells with the same position in the string are connected through the control gates by a wordline (WL) A plane contains a certain number of blocks that are connected through the same BL.