IEEE Computer Architecture Letters

PrePrint: Exploiting Internal Parallelism of Flash-based SSDs

For the last few years, the major driving force behind the rapid performance improvement of SSDs has been the increment of parallel bus channels between a flash controller and flash memory packages inside the solid-state drives (SSDs). However, there are other internal parallelisms inside SSDs yet to be explored. In order to improve performance further by utilizing the parallelism, this paper suggests request rescheduling and dynamic write request mapping. Simulation results with real workloads have shown that the suggested schemes improve the performance of the SSDs by up to 15% without any additional hardware support.

PrePrint: A Phase Change Memory as a Secure Main Memory

Phase change memory (PCM) technology appears as more scalable than DRAM technology. As PCM exhibits access time slightly longer but in the same range as DRAMs, several recent studies have proposed to use PCMs for designing main memory systems. Unfortunately PCM technology suffers from a limited write endurance; typically each memory cell can be only be written a large but still limited number of times ($10^7$ to $10^9$ writes are reported for current technology). Till now, research proposals have essentially focused their attention on designing memory systems that will survive to the average behavior of conventional applications.However PCM memory systems should be designed to survive worst-case applications, i.e., malicious attacks targeting the physical destruction of the memory through overwriting a limited number of memory cells. In this paper, we propose the design of a secure PCM-based main memory that would by construction survive to overwrite attacks.

PrePrint: Using Resampling Techniques to Compute Confidence Intervals for the Harmonic Mean of Rate-Based Performance Metrics

Rate-based metrics such as floating point operations per second, instructions per cycle and so forth are commonly used to measure computer performance. In addition to the average or mean performance of the metric, indicating the precision of the mean using confidence intervals helps to make informed decisions and comparisons with the data. In this paper, we discuss the determination of confidence intervals for the harmonic mean of rate-based metrics using two statistical resampling techniques - Jackknife and Bootstrap. We show using Monte Carlo simulations that resampling indeed works as expected, and can be used for generating confidence intervals for harmonic mean.

IEEE Computer Architecture Letters - July-December 2009 (Vol. 8, No. 2)

IEEE Computer Architecture Letters