### Optimal directory placement on disk storage devicesOptimal directory placement on disk storage devices

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 Author Calderbank, A. R. ♦ Coffman, E. G. ♦ Flatto, Leopold Source ACM Digital Library Content type Text Publisher Association for Computing Machinery (ACM) File Format PDF Copyright Year ©1988 Language English
 Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science Abstract Two mathematical models dealing with optimal placement of directories on disk devices are analyzed. Storage addresses on the disk are approximated by points in the interval [0, 1]. Requests for information on the disk are represented by a sequence of file names. To process a request, a read-write head is first moved to a directory kept on the disk that specifies the address of the file, and then a head is moved to the specified address. The addresses are assumed to be independent and uniform on [0,1].In the first model we consider a system of two heads separated by a fixed distance $\textit{d}$ and a directory situated at 0 ≤ $\textit{x}$ ≤ 1. In the second model we consider a system consisting of one head and $\textit{n}$ ≥ 2 directories at 0 ≤ $\textit{x}1$ < $\textit{x}2$ < … < $\textit{x}\textit{n}$ ≤ 1. For both models we study the problem of finding those values of the parameters that minimize the expected head motion to process a request in statistical equilibrium. ISSN 00045411 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 1988-04-01 Publisher Place New York e-ISSN 1557735X Journal Journal of the ACM (JACM) Volume Number 35 Issue Number 2 Page Count 14 Starting Page 433 Ending Page 446

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Source: ACM Digital Library