Analysis of flash memory wear based on cache configuration and available memory

Sammanfattning: This thesis aimed at examining the effects of file and disk cache for certain writing patterns and file sizes for Beijer Electronic's human machine interface (HMI) panels with the focus on write amplification factor (WAF). The goal was to determine optimal configurations to reduce WAF for different use cases to prolong the lifetime of Beijer Electronic's HMI panels. A test application and logs were created to measure commands sent over the bus for chosen tests. It was found that write amplification decreased naturally as file sizes grew. It was also found that enabling disk cache without file cache had the most negative impact on the write amplification factor, but that enabling file cache together with disk cache reduced the negative effect as well as improved writing speed. Furthermore, only enabling file cache or not enabling any form of cache resulted in the lowest write amplification factor for file sizes between 10 and 10000 KB, however always resulting in slower execution times than configurations with both caches enabled. It was also found that operating the panels at close to max capacity reduced writing speed because of the internal wear-leveling required for the SD cards during tests to not wear out prematurely, but no increase in write amplification factor was measured.