Afternoon all – HAPPY FRIDAY!
Data is stored on a Solid State Drive (SSD) using a fundamentally different technology than traditional Hard Disk Drives (HDDs). SSDs use NAND flash memory to store data, which is a type of non-volatile storage technology. Here’s a simplified overview of how data is stored on an SSD:
NAND Flash Memory: An SSD consists of multiple NAND flash memory chips. These chips are made up of memory cells that can store data as electrical charges. Each memory cell can represent a binary value (0 or 1).
Pages and Blocks: NAND flash memory is organized into pages and blocks. A page is the smallest writable unit of an SSD and typically ranges from 4KB to 16KB in size. Pages are grouped into blocks, which are larger and can contain multiple pages (e.g., 128 pages per block).
Writing Data: When data is written to an SSD, it is first stored in a buffer or cache. This data is then programmed into empty pages within the NAND flash memory. SSDs employ a process called wear-leveling to evenly distribute write and erase cycles across memory cells to extend the lifespan of the drive.
Erasing Data: SSDs cannot modify data directly in place like HDDs can. Instead, when data needs to be updated or deleted, the entire block containing the data is marked as invalid and can be erased. A new block is then used to write the updated or new data. This process, called garbage collection, is managed by the SSD’s controller.
Reading Data: To read data from an SSD, the controller retrieves the data from the appropriate pages in the NAND flash memory. SSDs are much faster at reading data compared to HDDs because there are no physical components involved in seeking and reading data.
TRIM Command: The TRIM command is used by the operating system to inform the SSD which blocks are no longer in use. This helps the SSD’s garbage collection process by allowing it to proactively erase and free up blocks, maintaining performance over time.
Overall, the use of NAND flash memory in SSDs results in faster data access times, lower power consumption, and greater durability compared to traditional HDDs. However, SSDs can have limited write endurance due to the finite number of write/erase cycles that each memory cell can endure. To mitigate this, SSDs use wear-leveling and error correction techniques to maintain data integrity and extend their lifespan. Advances in SSD technology continue to improve performance, capacity, and durability while reducing costs – Have a GREAT weekend!
