HomeFiction #5: All SSDs have sufficient ECC protection
Fact #5: SandForce enables ECC protection that exceeds the capabilities of SSDs and leading HDDs
ECC has been a key part of storage systems for many years. Its purpose is to include information in the data being transmitted that enables the recipient to fix a defined number of errors without requiring the data to be retransmitted. However, not all ECC protection mechanisms are created equal and they certainly can provide different levels of data reliability. The SSD specification for the number of bits that can be read before a sector error occurs is usually 10^15 bits read. That is a big number until you calculate how fast you can read that much data. Using a read transfer rate of 250MB/s at a 40% duty cycle a sector error will occur about every 14 days. That would be 130 times in a 5 year period.
Top performing HDDs have protection up to 10^16 bits read. If the read rate of the HDD were capable of hitting 250MB/s it would have these sector errors about 2.5 times per year, or 12 times in 5 years. Today these drives only transfer in the 70-100MB/s range, but that only improves the rate to about once per year (or 5 times in 5 years).
DuraClass technology provides superior ECC protection even with MLC memory. This protection provides for one sector error for each 10^17 bits read. That equates to only one error every 3.9 years!
