This is an old revision of the document!
Intermittent computing, by its very nature, requires non-volatile memory to store data between outages. However, many typical non-volatile options (such as NAND) are infeasible for a variety of reasons (such as write limitations1)). As a result, most research and development has focused on a few specialized forms of non-volatile memory.
Most common in MSP430 microcontrollers.