Egalitarian ORAM: Wear-Leveling for ORAM

While non-volatile memories (NVMs) provide several desirable characteristics like better density and comparable energy efficiency than DRAM, DRAM-like performance, and disk-like durability, the limited endurance NVMs manifest remains a challenge with these memories. Indeed, the endurance constraints of NVMs can prevent solutions that are commonly employed for other mainstream memories like DRAM from being carried over as-is to NVMs. Specifically, in this work we observe that, Oblivious RAM (ORAM) primitive, the state-ofart solution to tackle memory bus side channel vulnerability, while widely studied for DRAMs, is particularly challenging to implement as-is for NVMs as it severely affects endurance of NVMs. This is so, as the inherent nature of ORAM primitive causes an order of magnitude increase in write traffic and furthermore, causes some regions of memory to be written far more often than others. This non-uniform write traffic as manifested by ORAM primitive stands to severely affect the lifetime of non-volatile memories (1% of baseline without ORAM) to even make it impractical to address this security vulnerabilit

하이브리드 메모리 구조에서 접근 패턴에 기반한 페이지 배치 알고리즘

학위논문 (석사)-- 서울대학교 대학원 공과대학 컴퓨터공학부, 2017. 8. 엄현상.Due to the high memory footprint pressure, the hybrid memory architecture consisting of small-sized DRAM and large-sized PCM has been regarded as a promising approach. This architecture aims at (1) alleviating the high power consumption caused by large-sized DRAM, and (2) harnessing the non-volatility and in-place update capability of PCM. Numerous studies have addressed the importance of page placement scheme between two different types of memory frames. Particularly, they have made every effort to provide good wear-leveling, hide the low write speed of PCM and reduce the power consumption. However, they lack one of the two points: (1) read-dominated workloads also decrease the system-wide energy efficiency and (2) excessive page migration should be avoided. In order to solve the abovementioned problems, we propose an access-pattern- aware page placement algorithm. Fundamentally, it uses page-leveling policy using multi-queue. To set the level of a page, it uses weighted access counting which puts a more emphasis on write accesses without ignoring read accesses. To minimize the number of migrations from DRAM to PCM, it performs state-transition-based recency checking for pages in DRAM. Our experimental results clearly demonstrate that it can reduce the average memory access time by up to 39% and the power consumption by up to 57%, respectively, compared to the previous approaches. Furthermore, they show that the PCM wear-out performance can be improved by 27%.Chapter 1 Introduction 1 Chapter 2 Background and Motivation 6 2.1 Memory Architecture with DRAM and NVRAM 6 2.2 Motivating Examples 8 Chapter 3 Solution 12 3.1 Overview 12 3.2 Page Leveling 15 3.3 Getting a Free Page Frame from DRAM 18 3.4 Recency Checking 21 Chapter 4 Experimental Evaluation 26 4.1 Experimental Setup 26 4.2 Effect of Recency Checking 31 4.3 Effect of page placement algorithm depending on w-based access frequency 33 4.3.1 Effect on the number of page migrations 34 4.3.2 Effect on the average memory access time and the power consumption 35 4.3.3 Effect on the Lifetime of PCM 39 4.4 Performance analysis performed while varying the DRAM size 40 4.5 Techniques for further performance improvements 43 Chapter 5 Related Work 49 Chapter 6 Conclusion 52 Bibliography 54 초록 57Maste

NASA Tech Briefs, Spring 1977

Topics: NASA TU Services: Technology Utilization services that can assist you in learning about and applying NASA technology; New Product Ideas: A summary of sel~ted innovations of value to manufacturers for the development of new products; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Life Sciences; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences

Bibliography of Lewis Research Center technical publications announced in 1988

This bibliography contains abstracts of the technical reports that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1988. Subject, author, and corporate source indexes are also included. All the publications were announced in the 1988 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Technology 2000, volume 1

The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

NASA Thesaurus. Volume 1: Hierarchical listing

There are 16,713 postable terms and 3,716 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary

NASA thesaurus. Volume 1: Hierarchical Listing

There are over 17,000 postable terms and nearly 4,000 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary and Volume 3 - Definitions

Bibliography of Lewis Research Center technical publications announced in 1992

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1992. All the publications were announced in the 1992 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses