Nand-flash memory is a flash memory, the internal nonlinear macro cell pattern, a cheap and effective solution to achieve a large capacity solid state memory. Nand-flash memory has a larger capacity, rewrite speed, etc, it is suitable for storing large amounts of data, so the industry has been more widely used, such as embedded products, including mobile phones, digital cameras and the like. Hong Wang is NAND flash semiconductor suppliers, its eMMC, UFS is currently most popular storage solutions, today ICMAX Hong Wang semiconductor come and share in the development process of NAND flash.
In 1989, Toshiba issued a NAND flash architecture, emphasizing lower cost per bit, higher performance, and is the same as the disk can be easily upgraded through the interface. In accordance with the storage division, NAND flash memory has developed four generations:
The first generation unit may store SLC per 1-bit data (1bits / cell), good performance, long life, can withstand 100,000 program / erase cycles, but the low volume, high cost, now very rare;
The second generation of each MLC cell can store 2-bit data (2bits / cell), performance, service life, capacity, as more balanced in all aspects, may be subjected to 10,000 program / erase cycles, there are only few high-end can be seen in the SSD ;
TLC third generation per unit may store 3-bit data (3bits / cell), performance, lifetime degradation, can withstand 3,000 program / erase cycles, the capacity can be made larger, the cost may be lower, it is the most popular;
QLC fourth generation per cell may store four bits of data (4bits / cell), performance, service life is further deteriorated, can withstand 1000 program / erase cycles, but easier lifting capacity, continue to reduce costs. 
Hong Wang semiconductor NOTE: Cell more per data storage cell, the higher the capacity per unit area, but leads to a different voltage states, the harder it controls, resulting in poorer particle stability, low life, their advantages and disadvantages. SLC is relative, the MLC 100% capacity, the lifetime is shortened to 1/10 SLC, MLC is relative, TLC 50% of capacity, shortened life of the MLC 1/20.
QLC time appear very early, but has not been too concerned about the people, it truly enter everyone's eyes, should be from 2015. The biggest advantage compared to particle QLC in front of several particles are inexpensive, high-capacity, although low P / E lifetime, but high-capacity well to make up for this weakness.
Currently in SLC, MLC, TLC, QLC flash memory particles, TLC has been the protagonist, QLC is the future trend, TLC have 3D-TLC and 2D-TLC two kinds, 3D-TLC again subdivided into 32 layers 3D-TLC , 3D-TLC layer 64 and layer 96 the latest 3D-TLC.
SLC is used enterprise-class server, MLC has gradually withdrawn from the market, the average user is currently TLC mainstream storage granules.