Filling the Memory Access Gap: A Case for On-Chip Magnetic Storage

For decades, the memory hierarchy access gap has plagued computer architects with the RAM/disk gap widening to about 6 orders of magnitude in 1999. However, an exciting new storage tech-nology based on MicroElectroMechanical Systems (MEMS) is poised to ll a large portion of this performance gap, delivering signicant performance improvements and enabling many new types of applications. This research explores the impact MEMS-based storage will have on computer systems. Working closely with researchers building MEMS-based storage devices, we examine the performance impact of several design points. Results from ve dierent applications show that MEMS-based storage can reduce application I/O stall times by 80{99%, with overall performance improvements ranging from 1.1 to 20 for these applications. Most of these improvements re-sult from the fact that average access times for MEMS-based storage are 5 times faster than disks (e.g., 1{3ms). Others result from fundamental dierences in the physical behavior of MEMS-based storage. Combined, these characteristics create numerous opportunities for restructuring the stor-age/memory hierarchy