Wear levelling

Wear levelling is a technique used by EEPROM ('flash') computer memory systems in order to spread wear caused by repeated writing evenly across a chip, and thus avoid wearing out specific sections of the chip.

This wear effect is due to the fact that EEPROM media has a finite number of write cycles before failing (1e5 to 1e6 cycles for modern media). These wear levelling techniques can either be done by built in microcontrollers or externally by specific file systems like for example JFFS2.