Q uick R ecall : A HW/SW Approach for Computing across Power Cycles in Transiently Powered Computers

Transiently Powered Computers (TPCs) are a new class of batteryless embedded systems that depend solely on energy harvested from external sources for performing computations. Enabling long-running computations on TPCs is a major challenge due to the highly intermittent nature of the power supply (often bursts of in-situ checkpointing technique for TPCs using FRAM that consumes only 30 nJ while decreasing the time taken for saving and restoring a checkpoint to only 21.06μ s , which is over two orders of magnitude lower than the corresponding overhead using flash. We have implemented and evaluated our technique, Q uick R ecall , using the TI MSP430FR5739 FRAM-enabled microcontroller. Experimental results show that our highly-efficient checkpointing translate to significant speedup (1.25x - 8.4x) in program execution time and reduction (∼3x) in application-level energy consumption.