Exploiting Half-Wits: Smarter Storage for Low-Power Devices

This work analyzes the stochastic behavior of writing to embedded flash memory at voltages lower than recommended by a microcontroller’s specifications to reduce energy consumption. Flash memory integrated within a microcontroller typically requires the entire chip to operate on common supply voltage almost double what the CPU portion requires. Our approach tolerates a lower supply voltage so that the CPU may operate in a more energy efficient manner. Energy efficient coding algorithms then cope with flash memory that behaves unpredictably. Our software-only coding algorithms (in-place writes, multiple-place writes, RS-Berger codes) enable reliable storage at low voltages on unmodified hardware by exploiting the electrically cumulative nature of half-written data in write-once bits. For a sensor monitoring application using the MSP430, coding with in-place writes reduces the overall energy consumption by 34%. In-place writes are competitive when the time spent on computation i...

• Type: Journal
• Year: 2011
• Where: FAST
• Authors: Mastooreh Salajegheh, Yue Wang, Kevin Fu, Anxiao Jiang, Erik G. Learned-Miller
• Keywords: Ash Memory, FAST 2011, Least Four Times, Operating System, Stochastic Behavior