Unified read requests

Een Jun Hwang, B. Prabhakaran

Research output: Contribution to journalArticle

Abstract

Most work on multimedia storage systems has assumed that clients will be serviced using a round-robin strategy. The server services the clients in rounds and each client is allocated a time slice within that round. Furthermore, most such algorithms are evaluated on the basis of a tightly specified cost function. This is the basis for well known algorithms such as FCFS, SCAN, SCAN-EDF, etc. In this paper, we describe a Request Merging (RM) module that takes as input, a set of client requests, and a set of constraints on the desired performance such as client waiting time or maximum disk bandwidth, and a cost function. It produces as output, a Unified Read Request (URR), telling the storage server which data items to read, and when the clients would like these data items to be delivered to them. Given a cost function of, a URR is optimal if there is no other URR satisfying the constraints with a lower cost. We present three algorithms in this paper, each of which accomplishes this kind of request merging. The first algorithm OptURR is guaranteed to produce minimal cost URRs with respect to arbitrary cost functions. In general, the problem of computing an optimal URR is NP-complete, even when only two data objects are considered. To alleviate this problem, we develop two other algorithms, called GreedyURR and FastURR that may produce sub-optimal URRs. but which have some nicer computational properties. We will report on the pros and cons of these algorithms through an experimental evaluation.

Original languageEnglish
Pages (from-to)203-224
Number of pages22
JournalMultimedia Tools and Applications
Volume20
Issue number3
DOIs
Publication statusPublished - 2003 Aug 1
Externally publishedYes

Fingerprint

Cost functions
Cost Function
Merging
Servers
Server
Multimedia Systems
Storage System
Waiting Time
Experimental Evaluation
Slice
Costs
NP-complete problem
Bandwidth
Module
Computing
Output
Arbitrary

Keywords

  • Cost function
  • Multimedia storage server
  • Optimality
  • Request merging

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Information Systems
  • Computer Graphics and Computer-Aided Design
  • Software
  • Theoretical Computer Science
  • Computational Theory and Mathematics

Cite this

Unified read requests. / Hwang, Een Jun; Prabhakaran, B.

In: Multimedia Tools and Applications, Vol. 20, No. 3, 01.08.2003, p. 203-224.

Research output: Contribution to journalArticle

Hwang, Een Jun ; Prabhakaran, B. / Unified read requests. In: Multimedia Tools and Applications. 2003 ; Vol. 20, No. 3. pp. 203-224.
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