Now showing items 1-15 of 15

    • Analysis of simple randomized buffer management for parallel I/O 

      Kallahalla, Mahesh; Varman, Peter J. (2004-04)
      Buffer management for a D-disk parallel I/O system is considered in the context of randomized placement of data on the disks. A simple prefetching and caching algorithm PHASE-LRU using bounded lookahead is described and ...
    • ASP: Adaptive Online Parallel Disk Scheduling 

      Kallahalla, Mahesh; Varman, Peter J. (1999)
      In this work we address the problems of prefetching and I/O scheduling for read-once reference strings in a parallel I/O system. We use the standard parallel disk model with D disks a shared I/O bu er of sizeM. We ...
    • Balancing Fairness and Efficiency in Tiered Storage Systems using Bottleneck-Aware Allocation 

      Varman, Peter J.; Wang, Hui (2014-02)
      Multi-tiered storage made up of heterogeneous devices are raising new challenges in allocating throughput fairly among concurrent clients. The fundamental problem is finding an appropriate balance between fairness to the ...
    • Bridging the Programming Gap between Persistent and Volatile Memory using WrAP 

      Giles, Ellis; Doshi, Kshitij; Varman, Peter J. (2013-05)
      Advances in memory technology are promising the availability of byte-addressable persistent memory as an integral component of future computing platforms. This change has significant implications for software that has ...
    • Competitive Parallel Disk Prefetching and Buffer Management1 

      Barve, Rakesh; Kallahalla, Mahesh; Varman, Peter J. (2000)
      We provide a competitive analysis framework for online prefetching and buffer management algorithms in parallel IrO systems, using a read-once model of block references. This has widespread applicability to key IrO-bound ...
    • Defragmenting the Cloud Using Demand-based Resource Allocation 

      Gulati, Ajay; Varman, Peter J. (2013-06)
      Current public cloud offerings sell capacity in the form of pre-defined virtual machine (VM) configurations to their tenants. Typically this means that tenants must purchase individual VM configurations based on the peak ...
    • Efficient Archivable Time Index: A Dynamic Indexing Scheme for Temporal Data 

      Verma, Rakesh M.; Varman, Peter J. (1994)
      We present a practical and asymptotically optimal indexing structure for a versioned timestamped database with step-wise constant data. Three version operations, insertions, updates, and deletes are allowed for the present ...
    • An Efficient Multiversion Access Structure 

      Varman, Peter J.; Verma, Rakesh M. (2007-05)
      An efficient multiversion access structure for a transaction-time database is presented. Our method requires optimal storage and query times for several important queries and logarithmic update times. Three version ...
    • Markov analysis of multiple-disk prefetching strategies for external merging 

      Sadananda Pai, Vinay; Schaffer, Alejandro A.; Varman, Peter J. (1994-06-06)
      Multiple-disk organizations can be used to improve the I/O performance of problems like external merging. Concurrency can be introduced by overlapping I/O requests at different disks and by prefetching additional blocks ...
    • Optimal Matrix Multiplication on Fault Tolerant VLSI Arrays 

      Varman, Peter J.; Ramakrishnan, I.V. (1989-02)
      A fault-tolerant array for matrix multiplication that explicitly incorporates mechanisms for easy testability and reconfigurability is described. All signals in the array travel only a constant distance (independent of ...
    • PC-OPT: Optimal Offline Prefetching and Caching for Parallel I/O Systems 

      Kallahalla, Mahesh; Varman, Peter J. (2002-11)
      Abstract—We address the problem of prefetching and caching in a parallel I/O system and present a new algorithm for parallel disk scheduling. Traditional buffer management algorithms that minimize the number of block misses ...
    • Placement-Related Problems in Shared Disk I/O 

      Sinclair, J.B.; Tang, J.; Varman, Peter J. (1996)
      In a shared-disk parallel I/O system, several processes may be accessing the disks concurrently. An important example is concurrent external merging arising in database management systems with multiple independent sort ...
    • Randomized Parallel Prefetching and Buffer Management 

      Kallahalla, Mahesh; Varman, Peter J. (1999)
      We show that deterministic algorithms using bounded lookahead cannot fully exploit the potential of a parallel I/O system. Randomization can be used to significantly improve the performance of parallel prefetching and ...
    • Tight Bounds for Prefetching and Buffer Management Algorithms for Parallel I/O Systems 

      Varman, Peter J.; Verma, Rakesh M. (1999-12)
      The I/O performance of applications in multiple-disk systems can be improved by overlapping disk accesses. This requires the use of appropriate prefetching and buffer management algorithms that ensure the most useful ...
    • WrAP: Managing Byte-Addressable Persistent Memory 

      Varman, Peter J.; Doshi, Kshitij (2012-10)
      Advances in memory technology are promising the availability of byte-addressable persistent memory as an integral component of future computing platforms. This change has significant implications for software that has ...