Accession Number : ADA180023

Title :   Directory Reference Patterns in a UNIX Environment.

Descriptive Note : Technical rept.,

Corporate Author : ROCHESTER UNIV NY DEPT OF COMPUTER SCIENCE

Personal Author(s) : Floyd,Rick

PDF Url : ADA180023

Report Date : Aug 1986

Pagination or Media Count : 39

Abstract : Data on directory references made in opening files have been collected from a 4.2BSD UNIX system supporting university research. An analysis of these data shows that paths are relatively 'long' (an average of 2.7 components to resolve per path) and that, in the absence of caching, name resolution overhead accounts for over 70% of the disk blocks referenced to open and use files. Directory references show strong locality, though, making caches an effective way to decrease this overhead. Simulations of an LRU whole directory cache show that a cache holding just 10 nodes achieves an 85% hit ratio. A number of other results on directory reference patterns are presented in this paper, along with a discussion of their implications for both local and distributed file systems. (Author)

Descriptors :   *COMPUTER FILES, PATHS, DATA MANAGEMENT, DIRECTORIES, PATTERNS

Subject Categories : Computer Programming and Software

Distribution Statement : APPROVED FOR PUBLIC RELEASE