A user-space file system for on-demand legacy desktop software  

作　　者：ZHANG YouHui 1,2 , SU GeLin 1,2 & ZHENG WeiMin 1,2 1 Department of Computer Science and Technology, Tsinghua University, Beijing 100084, China 2 Tsinghua National Laboratory for Information Science and Technology, Tsinghua University, Beijing 100084, China 

出　　处：《Science China(Information Sciences)》2011年第6期1142-1150,共9页中国科学（信息科学）（英文版）

基　　金：supported by the National High Technology Research and Development Program of China(GrantNo.2008AA01A201);the National Basic Research Program of China(Grant No.2007CB310900)

摘　　要：Someuser-level virtualization technologies have been usedto convert legacy software（1ike the existing Windows desktop applications）into the on-demand software without any modification.To give the client a friendly and compatible method to access on-demand legacy software across the Internet,this paper presentsa cli-ent end filesy stem for this usage case.It isa Windowsu ser-space file system based on the cloud storage （where the on-demand software is stored）,which converts the local file system accesses into remote visits.Quite a few optimizations are adopted and adjusted to suit the file-access-pattern of on-demand software,includ ing thelo cal cache,metadata/data/software pre-fetch and content-addressable storage（CAS）,to decrease the number of remote visitsand/or to overlap IO（input/output）operations with software execution.Detailed access-patternanalyses are also presented.This file system has been implemented and tests showthat it is practical for muchdaily-used software-a local cache of limited size can provide up to80%hit ratio and the corresponding overhead of running-time is about37%.Owing to this method,on any compatible and networked computer,a user canuse his/her personMized software conveniently although it does not exist on the local host.Someuser-level virtualization technologies have been usedto convert legacy software（1ike the existing Windows desktop applications）into the on-demand software without any modification.To give the client a friendly and compatible method to access on-demand legacy software across the Internet,this paper presentsa cli-ent end filesy stem for this usage case.It isa Windowsu ser-space file system based on the cloud storage （where the on-demand software is stored）,which converts the local file system accesses into remote visits.Quite a few optimizations are adopted and adjusted to suit the file-access-pattern of on-demand software,includ ing thelo cal cache,metadata/data/software pre-fetch and content-addressable storage（CAS）,to decrease the number of remote visitsand/or to overlap IO（input/output）operations with software execution.Detailed access-patternanalyses are also presented.This file system has been implemented and tests showthat it is practical for muchdaily-used software-a local cache of limited size can provide up to80%hit ratio and the corresponding overhead of running-time is about37%.Owing to this method,on any compatible and networked computer,a user canuse his/her personMized software conveniently although it does not exist on the local host.

关 键 词：on-demand software software as a service user-space file system cloud storage 

分 类 号：TP316.7[自动化与计算机技术—计算机软件与理论]