Classifying Algorithm Based on a Fuzzy Neural network for the control of a Network Attached Opti

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OPTOELECTRONICS LE|TTERS VoI 2 No 6。15 Nov.2006 

LIU Xuan ,JIA Hui-bo,and CHENG Ming 

Optical Memory National Engineering Research Center,Tsing ̄a 

(Received 25 August 2006) 

A new anal、,ticaI method for improving the performance of a network a ̄ached opticaIjukebox is pres- ented by means of artificiaI neuraI networks.Through analyzing operation(request)process in this sys- 

tem,the mathematics modeI and algoritl ̄n are built for this storage system,and then a classified meth- 

od based on artificiaI neuraI networks for this system is proposed.Simulation results testified the feasi- 

billty and vaIidity of the proposed method that it could overcome the drawbacks of the frequent I/0 op- 

eration and provide an effective way for using the Network Attached OpticaI Jukebox. 

CLC number:TP183 I:)ocum ̄nt cOde:A Article lD:1673.1905(2006)06—0459-04 

In our previOUS work[ 一引,we established a new ap— 

proach which has mass disk buffer in optical i ukebox 

and can be accessed directly from network in a mass 

storage system,and named this system as network atta— 

ched optical j ukebox(NAOJ).In order to improve its 

performance further,a new approach based on a fuzzy 

artificial neural network is presented in this letter. 

As we usually know,the network surrounding is very 

complicated,and the optical jukebox has its disadvantage 

due to mechanical movement,which limits its applica- 

tion.In order to improve its access speed it is necessary to analyze different cases in the application models for 

the Network Attached Optical Jukebox. In this paper,we firstly establish a preferential queu~ 

ing network model for NAOJ,and then based on this 

model we use a neural network method to classify the 

users requests.The simulation results testified the feasi- 

bility and validity of the proposed method that it could 

overcome the drawbtLcks of the frequent I/0 operation 

and provide an effective way for using NAOJ. 

The storage model of NAOJ consists of a network 

service module,a magnetic disk cache module and an op- 

tical i ukebox module.The framework is shown in Fig.1. 

IDE magnetic 

1 The queuing model for Network Attad ̄Optie ̄Juke- 

box 

* E-mail:liu2xuan99@mails.tsinghua.edu.cn For one operation(request)from I/O port,the net— 

work service module needs to complete two actions,i.e. 

receiving the user request and seeding required data to 

the user[ .The NAOJ will complete the following steps 

for each request. 

According to the operation principle of Network Atta— ched Optical Jukebox ̄ and the idea of hierarchical stor— 

age system,when an accessing request comes,it first 

searches in the disk cache.If the data needed is not 

stored in the disk cache,we will access the optical j uke— 

box.At this time.the data that the user needs may be 

any one under the three situations below: 

1.The data are being transferred to another user, 

which means the data are hot in this period,but it was 

not prefetched to the disk cache before.Therefore,the 

situation is that the other userg requests come when the 

data are transferring to the first user; 

2.The data are not being transferred,but it is stored 

in the disk placed in the driver; 

3.The data are not stored in the disk placed in the 

driver. 

However,the hit rate of that the data are right in the 

disk cache is quite limited,because it is correlated with 

the user accessing distributing,demanded data quantity 

and many other factors.This leads to that the accessing 

to the optical iukebox is still more frequent.As the re— 

sult,a great part of the optical jukebox response time 

wastes on the machine operation such as change disks. 

Therefore,a further study on the user s accessing will 

make great help to the improvement of the whole sys— 

tem De ̄ormance of Network Attached Optical Jukebox. 

Userg requests are partitioned into N levels.The first 

level has the highest priority,and will be dealt with 

firstly by the storage management server.The second 

level has the secondary priority.And the N-th level has 

the lowest priority and U be dealt with lastly. 

A non-preemptive priority queuing model,that i

s,if 维普资讯 http://www.cqvip.com ・0460・ 

the system is busy the users request that has the priori— 

ty can t preempt the service window,but queue before the lower-or-non priority reques{ , . 

Assume that is the arriving rate of the i level, is 

the average request access service rate of the i level,Ti 

is the service time for the request of the i level where 1 

N,and is the average arriving rate of all the re— 

quire.Obviously we only know as a parameter in this 

model because is not surveyed in real circumstance. 

Then we have 

T【 一 1 』£=E1 l一一 

Let 一 t/ 一 Ti.Since the requests of Ist to N lev—