Dr. Eitan Bachmat Senior lecturer Address:       Department of Computer Science Ben-Gurion University P.O. Box 653 Beer-Sheva 84105, Israel Office: Building 37, Room 119 Email: ebachmat@cs.bgu.ac.il Phone: +972 (0) 8 647 7858 Fax: +972 (0) 8 647 7650 Office hours: Wednesday 12–2

Research

I work in the area of systems design and analysis. Most of the systems which I develop or analyze are computer systems. More specifically most of my development and analysis involves storage systems. Within storage systems I am particularly fond of systems which contain disk drives. Disk drives are interesting because they involve mechanical motion which makes them much slower than any other computing components. While in recent years they have been facing stiff competition from faster non-mechanical devices, they still play an important role. The mechanical nature of disk drives makes the mathematics involved in their analysis interesting.

A book

• E. Bachmat, Mathematical adventures in performance analysis. draft. Book to be published by Birkhauser.

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  My Papers

  • E. Bachmat, V. Khachaturov and R. Kuperman, Optimal back-to-front airplane boarding. Phys. Rev. E 87, 062805 (2013). The detaled calculations without the simulation results or the general analysis are given in
  • V. Khachaturov, E. Bachmat, Optimal back-to-front airplane boarding
  • E. Bachmat, I. Elhanan, Analysis of the GSTF disk scheduling algorithm. Proceedings of the MAMA 2013 workshop.
  • G. Lipetz, E. Hazan, A. Natanzon, E. Bachmat, Automated tiering in a QoS environment using sparse data.
  • A. Natanzon, E. Bachmat, , Virtual point in time access, proceedings of SYSTOR 2013. Virtual access presentation by Assaf
  • N. Milo, S. Zakov, E. Katzenelson, E. Bachmat, Y. Dinitz and M. Ziv-Ukelson, Unrooted unordered homeomorphic subtree alignment of RNA trees. Algorithms for Molecular Biology 2013, 8:13. Preliminary conference version in the next item.
  • N. Milo, S. Zakov, E. Katzenelson, E. Bachmat, Y. Dinitz and M. Ziv-Ukelson, RNA Tree Comparisons via Unrooted Unordered Alignments. Proceedings of WABI 2012.
  • E. Bachmat, A. Natanzon, Analysis of SITA queues with many servers and spacetime geometry. Performance evaluation review, special issue for proceedings of the MAMA 2012 workshop, To appear 2013.
  • A. Natanzon, E. Bachmat, Dynamic synchronous/asynchronous replication. Accepted to ACM TOS.
  • E. Bachmat On queues and numbers.
  • A. Natanzon, A. Winokur, E. Bachmat, Blackbox replication: Breaking the latency limits.
  • R. Shaull, E. Bachmat, T. Ron, A. Littman, H. Mor and E. Shmidov, Enterprise storage provisioning with flash drives.
  • H. Sarfati and E. Bachmat, Analysis of the Task Assignment based on Guessing Size (TAGS) policy.
  • E. Bachmat The analysis of PQRS and other bias models.
  • E. Bachmat and H. Sarfati, Analysis of SITA policies. Performance evaluation vol 67(2), 102-120, 2010.
  • M. Kleider, B. Rafaeli, B. Weiss and E. Bachmat, Golden-Ratio Sampling for Scanning Circular Microphone Arrays, IEEE Transactions on Audio, Speech & Language Processing 18(8), 2091-2098, 2010.
  • L. Aronovich, R. Asher, E. Bachmat, H. Bitner, M. Hirsch and S. Klein, The design of a similarity based deduplication system. Proceedings of SYSTOR 2009, paper number 6.
  • E. Bachmat, D. Berend, L. Sapir, S. Skiena, and N. Stolyarov, Analysis of airplane boarding times. Operations research 57(2): 499-513, 2009.
  • E. Bachmat, Discrete space-time and its applications. In, "Random matrices, Integrable systems and Applications: A conference in honor of Percy Deift's 60th birthday", edited by: J. Baik, L-C. Li, T. Kriecherbauer, K. McLaughlin and C. Tomei, Contemporary Mathematics book series, American Mathematical Society, Providence RI., 2008.
  • E. Bachmat and M. Elkin, Bounds on the performance of back-to-front airplane boarding policies . Operations research letters 36(5), 597-601, 2008.
  • E. Bachmat, T.K. Lam, and A. Magen, Analysis of set-up time models - a metric perspective . Theoretical computer science, vol 401, 172-180, 2008.
  • B. Rafaely, B. Weiss and E. Bachmat, Spatial Aliasing in Spherical Microphone Arrays. IEEE Transactions on Signal Processing, vol 55(3), 1003-1010, 2007.
  • E. Bachmat, Analysis of disk scheduling with linear seek functions, increasing sunsequences and space-time geometry. Algorthmica, vol 49(3), 212-231, 2007.
  • R. Arnan, E. Bachmat, T.K. Lam and R. Michel, Dynamic data reallocation in disk arrays . ACM transactions on storage, vol 3(1), 2007.
  • E. Bachmat, D. Berend, L. Sapir and S. Skiena, Optimal boarding policies for thin passengers. Advances in applied probability, vol 39(4), 1098-1114, 2007.
  • E. Bachmat, D. Berend, L. Sapir, and S. Skiena and N. Stolyarov, Analysis of airplane boarding via space-time geometry and random matrix theory. Journal of physics A: mathematical and general, vol 39, L453-459, 2006.
  • N. Alon and E. Bachmat Regular graphs whose subgraphs tend to be acyclic , Random structures and algorithms, vol 29(3), 324-337, 2006.
  • E. Bachmat and V. Braverman Batched disk scheduling with delays. Performance evaluation review, special issue on design, implementation and performance of storage systems, vol 33(4),36-41, 2006.
  • E. Bachmat and T.K. Lam On the effect of a configuration choice on the performance of a Mirrored storage system , Journal of parallel and distributed computing, 65(3), 382-395, 2005.
  • E. Bachmat On the performance of D-redundant disk systems , Proceedings of QEST 2005, 105-113, 2005.
  • A. Stotland, A. Pomarenko, E. Bachmat, and D. Cohen The information entropy of quantum-mechanical states , Europhysics letters, Vol. 67, 700-706, 2004.
  • O. Glinansky, D. Goren-Bar, and E. Bachmat, An efficient algorithm for handling requests under conditions of uncertainty, Communications in dependability and quality management, Vol. 6(2), 30-46, 2003.
  • J. El-Sana and E. Bachmat, Optimized view dependent rendering for large datasets, Proceedings of IEEE visualization, Boston, 77-84, Ma., 2002.
  • E. Bachmat and J. Schindler, Methods for performing secondary tasks in disk arrays , Performance evaluation reviews, special issue devoted to Proc. of SIGMETRICS 2002, vol. 30(1), 55-65, 2002.
  • E. Bachmat Average case analysis for batched disk scheduling and increasing subsequences , Proceedings of STOC, 277-286, 2002.
  • E. Bachmat and E. Goren, On the non ordinary locus in Hilbert-Blumenthal surfaces, Mathematische Annalen, Vol. 313, 229-254, 1999.
  • E. Bachmat, A Fourier transform construction for Arakelov Chow groups of an arithmetic Abelian scheme, Duke Journal of Mathematics, IMRN section, Vol. 7, 227-232, 1993.

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  Related to my work

  • P. Sarnak, Letter to Eitan Bachmat on positive definite L-functions., April, 2011.
  • P. Ball, Warped geometry speeds airline boarding ., Nature news, 9 Dec, 2005.
  • Its just plain stupid ., The Sun, 21 Dec, 2005.
  • N. Zamiska, Plane geometry. scientists help speed boarding of aircraft (local copy)., Front page of the Wall Street Journal, 2 Nov, 2005.
  • B. Longstaff, Let Einstein help you board your plane., New Scientist (top story!) July 29, 2006 issue 2562.

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    Patents

    • Bachmat E. and Vishlitzky N., Method and apparatus for reading data from mir- rored logical volumes on a physical disk drive U.S. patent number 5,819,310, 1998.
    • Bachmat E., caching system and method providing aggressive prefetch, U.S. patent number 6,003,114, 1999.
    • Vishlitzky N., Ofek Y. and Bachmat E., Redundant storage mirroring by logical volume with diverse reading process, U.S. patent number 5,987,566, 1999.
    • Bachmat E. and Bachmat H., System for distributing volumes to an HSM system front end, U.S. patent number 5,974,515, 1999.
    • Vishlitzky N. and Bachmat E., System and method for accessing records in a cache slot which are associated with a current owner storage element or at least on previous owner storage element, U.S patent number 5,900,009, 1999.
    • Bachmat E.,System for improving the performance of a disk storage device by recon- iguring a logical volume of data in response to the type of operations being performed, U.S. patent number 6,122,685, 2000.
    • Mason R., Ofek Y., Vishlitzky N., Arnon D. and Bachmat E., Dynamic adjustment of mirror service policy for logical volumes in a disk drive system based on collected statistics, U.S. patent number 6,112,257, 2000.
    • Bachmat E. and Moreshet J., Method for exchanging data blocks on disk storage devices utilizing disk access statistics and testing for the effect of a change, U.S. patent number 6,088,766, 2000.
    • Bachmat E., Method for exchanging logical volumes in a disk array storage device in response to statistical analysis and preliminary testing, U.S. patent number 6,061,761, 2000.
    • Bachmat E., Remote cache utilization for mirrored mass storage subsystem, U.S. patent number 6,275,897, 2001.
    • Bachmat E., System for improving performance of a disk storage device by recon- iguring a logical volume of data in response to the type of operations being performed, U.S. patent number 6,272,571, 2001.
    • Bachmat E., Load balancing method for exchanging data in different physical disk storage devices in a disk array storage device independently of data processing system operation, U.S. patent number 6,237,063, 2001.
    • Bachmat E., Program and apparatus for balancing activity of disk storage devices in response to statistical analysis and preliminary testing, U.S. patent number 6,487,634, 2002.
    • Bachmat E., Ofek Y., Lam T.K., Dubrovsky V. and Michel R., Maximizing sequen- tial output in a disk array storage device, U.S. patent number 6,442,650, 2002.
    • Lam T.K., Bachmat E., Michel R. and Dubrovsky V., method for analyzing disk seek times in a disk array storage device, U.S. patent number 6,405,282, 2002.
    • Michel R., Lam T.K., DesRoches D., Dubrovski V. and Bachmat E., Intra disk swapping of data storage volumes, U.S. patent number 6,665,771. 2003.
    • Michel R., Lam T.K. and Bachmat E., Determining seek times, U.S. patent number 6,614,616, 2003.
    • Mason R., Bachmat E. and Lam T.K., Dynamic mirror service policy with seek ad- justments in a non- physical mirrored storage environment, U.S. patent number 6,611,897, 2003.
    • Bachmat E., Ofek Y.,Lam T.K., Dubrovsky V. and Michel R., maximizing sequen- tial output in a disk array storage device, U.S. patent number 6,584,545, 2003.
    • Arnon D. and Bachmat E., Mirrored drive performance using matching algorithms, U.S. patent number 6,775,739, 2004.
    • Bachmat E., Program and apparatus for balancing activity of disk storage devices in response to statistical analyses and preliminary testing, U.S. patent number 6,766,416, 2004.
    • Bachmat E., Lam T.K., Zakai A., Michel R., Ofek Y., Schreber M. and Dubrovsky V., Load balancing on disk array storage device, U.S. patent number 6,711,649, 2004.
    • Bachmat E., Lam T.K., Michel R. and Dubrovsky V., Method for analyzing disk seek times in a disk array storage device, U.S. patent number 6,694,405, 2004.
    • Michel R., Lam T.K. and Bachmat E., Swapping data storage volumes, U.S. patent number 6,851,019, 2005.
    • Mason R.S., Bachmat E. and Leprohon D., Utilizing disk cache as part of distributed cache, U.S. patent number 6,862,659, 2005.
    • Lam .K., Michel R. and Bachmat E., Method for determining seek times in a disk array storage device, U.S. patent number 6,917,569, 2005.
    • Bachmat E., System and method for assesing the effectiveness of a cache memory or portion thereof using FIFO or LRU utilization statistics, U.S. patent number 7,139,872, 2006.
    • E. Bachmat, H. Bachmat, and R. Arnan, Providing data indicative of the performance of a competing algorithm and an incumbent algorithm, U.S. patent number 7,181,727, 2007.
    • Hirsch M., Bitner H., Aronovich L., Asher R., Bachmat E. and Klein S., System and method for efficient data searching, storage and reduction, U.S. patent number 7,523,098, 2009.

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    In preparation

    • E. Bachmat, Topics in performance analysis, Book in preparation, hopefully sometime in 2011.
    • E. Bachmat, Queues in the mini-market and Fermat's last theorem.
    • E. Bachmat, Queues in the super-market and curvature in space-time.
    • E. Bachmat Does god play dice after all? A probabilistic interpretation for Einstein's law of dynamics.
    • E. Bachmat, Cache algorithms for bias models and a theorem of B. Host.
    • E. Bachmat, Power management of M/M/1 queues and theta functions.

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      Teaching

      • For the last two years I have been head of the teaching comittee of the department of computer science.
      • Storage systems, data structures, Topics in performance analysis.
      • This year I taught the course "Topics in performance analysis" which was based on my book draft. Some of the material overlaps with my storage systems course. The following course notes (4 parts in Hebrew) were taken by Olga Sibiryova, who kindly permitted me to post them, Part 1, Part 2, Part 3, part 4, test questions and more test questions Good luck.

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      Graduate Students

      • Nimrod Milo, PhD.
      • Assaf Natanzon, PhD.
      • Ilan Elhanan, MsC.
      • Gal Lipetz, MsC.
      • Etai Hazan, MsC.
      • Vassilli Khachaturov, MsC, graduated, 2008.
      • Noam Ben-Ami, MsC, graduated, 2008.
      • Vassilii Khachaturov, MsC, Graduated.