What Does Write Cycle Mean?
The write cycle is the measure of endurance or life for a solid state drive (SSD) and most flash-based storage devices. The write cycle encompasses the process of writing and erasing data in a multi-level cell (MLC) NAND chip, which eventually degrades the chip to the point of failure. It can be thought of like an eraser on a pencil slowly wearing away, until it is no longer able to erase.
The write cycle is also known as the write/erase cycle or program/erase cycle.
Techopedia Explains Write Cycle
Write cycle is basically an SSD’s wear-and-tear rating, indicating how many times NAND flash chips can be written and rewritten. When SSDs first came out, they were quite expensive but their write cycle rating was around 100,000, which is massive compared to today’s 2000 to 3000 write cycle range from common SSDs. However, their throughput and input/output operations per second (IOPS) were 10 times and 100 times slower respectively than what is commonly available today.
Because of the increasing demands for faster capacity, IOPS and throughput, SSD manufacturers have continuously shrunk the size of the NAND chip, which has the downside of lowering endurance. To counter the lowered write cycle, they have put in place smarter flash controller management systems that minimize the number of write cycles consumed by the SSD, either by delaying the writing of data by adding buffers or by implementing wear leveling, which spreads the load across the entire device rather than writing and erasing in the same memory location.