Flash Module with DRAM Buffer

Cervoz designs an additional DRAM chip into specific flash modules to increase both the products’ performance and endurance. A DRAM chip in a flash module functions the way a cache does in hard disk. While the flash module is in operation, the controller throws small amounts of data into the DRAM chip. In turn, the chip acts as a directory that assists in allocating the data to the assigned positions. With the assist of the DRAM, the response time is shortened, and thus performance improved.

By using the DRAM chip as a buffer, the flash module gains improved endurance. Unlike flash storage, DRAM is volatile and does not have a finite number of program/erase cycles. Thus, when the controller throws small amounts of data to the DRAM instead of directly into the flash storage, the DRAM buffer can collect them to a block-size data before delivering to the flash storage where it would be processed as a block. Without the buffer, data of any size would be passed to the flash storage and processed to erase one time, regardless of how small  the data is, which in the long run quickly wears down the module more quickly. The DRAM buffer thus decreases the number of P/E cycles the flash storage must perform, making it last longer to enhance storage endurance.

This solution is ideal for applications of long-term use which persistently requests the writing of large amounts of small-sized data. The technology prevents the unnecessary shortening of the application’s lifespan.