Brigham Young University BYU ScholarsArchive Theses and Dissertations 2009-07-01 Finding Alternatives to the Hard Disk Drive for Virtual Memory Bruce Albert Embry Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Computer Sciences Commons BYU ScholarsArchive Citation Embry, Bruce Albert, "Finding Alternatives to the Hard Disk Drive for Virtual Memory" (2009). Theses and Dissertations. 1727. https://scholarsarchive.byu.edu/etd/1727 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. FINDING ALTERNATIVES TO THE HARD DISK DRIVE FOR VIRTUAL MEMORY by Bruce A. Embry A thesis submitted to the faculty of Brigham Young University In partial fulfillment of the requirements for the degree of Master of Science School of Technology Brigham Young University August 2009 BRIGHAM YOUNG UNIVERSITY GRADUATE COMMITTEE APPROVAL Of a thesis submitted by Bruce A. Embry This thesis has been read by each member of the following graduate committee and by majority vote has been found to be satisfactory. Date B a r r y M. Lunt, Chair Date C. Richard G. Helps, Member Date Michael G. Bailey, Member BRIGHAM YOUNG UNIVERSITY As chair of the candidate’s graduate committee, I have read the thesis of Bruce A. Embry in its final form and have found that (1) its format, citations, and bibliographical style are consistent and acceptable and fulfill university and department style requirements; (2) its illustrative materials including figures, tables, and charts are in place; and (3) the final manuscript is satisfactory to the graduate committee and is ready for submission to the university library. Date B a r r y M. Lunt Chair, Graduate Committee Accepted for the Department Val D. Hawks Director, School of Technology Accepted for the College Alan R. Parkinson Dean, Ira A. Fulton College of Engineering and Technology ABSTRACT FINDING ALTERNATIVES TO THE HARD DISK DRIVE FOR VIRTUAL MEMORY Bruce A. Embry School of Technology Master of Science Current computer systems fill the demand of operating systems and applications for ever greater amounts of random access memory by paging the least recently used data to the hard disk drive. This paging process is called “virtual memory,” to indicate that the hard disk drive is used to create the illusion that the computer has more random access memory than it actually has. Unfortunately, the fastest hard disk drives are over five orders of magnitude slower than the DRAM they are emulating. When the demand for memory increases to the point that processes are being continually saved to disk and then retrieved again, a process called “thrashing” occurs, and the performance of the entire computer system plummets. This thesis sought to find alternatives for home and small business computer users to the hard disk drive for virtual memory which would not suffer from the same long delays. Virtual memory is especially important for older computers, which often are limited by their motherboards, their processors and their power supplies to a relatively small amount of random access memory. Thus, this thesis was focused on improving the performance of older computers by replacing the hard disk drive with faster technologies for the virtual memory. Of the different technologies considered, flash memory was selected because of its low power requirements, its ready availability, its relatively low cost and its significantly faster random access times. Two devices were evaluated on a system with a 512MB of RAM, a Pentium 4 processor and a SATA hard disk drive. Theoretical models and a simulator were developed, and physical performance measurements were taken. Flash memory was not shown to be significantly faster than the hard disk drive in virtual memory applications. ACKNOWLEDGMENTS I wish to thank Dr. Barry Lunt for his insightful critiques of this thesis, along with his friendship and encouragement. Professor Richard Helps is acknowledged for his ever vigilant devil’s advocacy which sharpened my own thinking. I am grateful to Dr. Michael Bailey for his support and research suggestions. I wish to thank the School of Technology for the use of computers and laboratory space. Most of all, I acknowledge the great debt that I owe my wife, JoAnne, for her patience and support during this long and arduous journey of exploration and self- discovery. TABLE OF CONTENTS 1 Introduction .......................................................................................................... 1 1.1 Computer Storage Systems ............................................................................ 4 1.2 Common Memory Devices............................................................................. 5 1.3 Additional Memory Devices .......................................................................... 9 1.4 Formulas ......................................................................................................... 9 1.5 Objective and Delineations .......................................................................... 17 1.6 Hypothesis .................................................................................................... 18 1.7 Methodology ................................................................................................ 18 1.8 Overview of Remaining Chapters ................................................................ 19 2 Review of Literature ........................................................................................... 21 2.1 Virtual Memory – an early pioneer .............................................................. 21 2.2 Virtual Memory – the computer science approach....................................... 27 2.3 Virtual memory - an IT approach ................................................................. 29 2.4 Solid State Devices – flash memory ............................................................. 31 2.5 Solid State Devices – other options .............................................................. 38 3 Methodology ........................................................................................................ 41 3.1 Triangulation ................................................................................................ 41 3.2 Theoretical Model ........................................................................................ 42 3.3 Published Data and Benchmarking .............................................................. 46 3.4 Virtual Memory Simulation ......................................................................... 47 vii 3.5 Physical Measurement .................................................................................. 48 4 Results 51 4.1 Model Systems .............................................................................................. 51 4.2 Theoretical Calculations ............................................................................... 55 4.3 Simulator Results .......................................................................................... 56 4.4 Physical Measurement Results ..................................................................... 58 4.5 Interpretation of Results ................................................................................ 62 5 Conclusions and Recommendations .................................................................. 67 5.1 Conclusions ................................................................................................... 67 5.2 Recommendations ......................................................................................... 69 6 References ............................................................................................................ 71 Appendix A. Glossary ............................................................................................... 77 Appendix B. Master Simulator Program Source Code ......................................... 83 Appendix C. Slave Simulator Program Source Code ............................................ 85 Appendix D. Physical Measurement Program Source Code ................................. 94 viii LIST OF TABLES Table 1-1 Characteristics of Common Memory Devices .....................................................6 Table 1-2 Performance Characteristics of Three-Level Memory Hierarchy ........................16 Table 4-1 Initial Information and Performance Data ............................................................52 Table 4-2 Regression Results of SiSoftware Sandra Measurements ....................................54 Table 4-3 Theoretical Calculations .......................................................................................56 Table 4-4 Simulator Results ..................................................................................................57 Table 4-5 Physical Performance Measurements ...................................................................60 Table 4-6 Physical Performance Comparisons .....................................................................61 Table 4-7 Comparison of Results .........................................................................................62 ix x LIST OF FIGURES Figure 4-1 Sequential Access Times .................................................................................... 63 Figure 4-2 Strided Access