TWI220609B - System and process for roaming thin clients in a wide area network with transparent working environment - Google Patents

Abstract

A multiple-application-server architecture model for thin-client/server (denoted MAS TC/S) is provided to allow users with thin-client devices to roam around a wide area network while experiencing transparent working environment. The MAS TC/S system includes major components of a display protocol, a multiple-application-server network, an application-server discovery protocol and a distributed file system. The application-server discovery protocol identifies the most appropriate application server for a thin-client device to connect to. The distributed file system includes a data-mining-based intelligent prefetching mechanism allowing achieving a working environment with access, location, and mobility transparencies in an efficient way for prompt service.

Description

1220609 V. Description of the invention (1) Field of the invention The present invention relates to a thin-client / server architecture, especially to a multiple-application server architecture (multi- application-server architecture), which enables users of thin-client devices to roam in a wide area network while experiencing a transparent working environment.

Background of the invention

The lightweight master-slave computing model is a kind of server-side computing model. Because of its low cost and the ability to quickly deploy applications to the server for execution, it has grown very quickly. The server-side computing model manages applications by focusing on the server side, rather than on the user's desktop computer, allowing companies or organizations to have more control over applications. The multi-user lightweight master-slave computing model further delegates all running applications to a single server. All applications and data deployment, management, and support are performed on the server. Therefore, the client device only uses a mouse, a keyboard, and a monitor to monitor the input, transmit the input to the server, and wait for the display content returned by the server. In the traditional lightweight master-slave computing mode, as shown in FIG. 1, one or more lightweight client devices 1a are connected to the application server 1b. As long as the lightweight client device 1 a is connected to the local network to which the application server 1 b belongs, no matter which lightweight client device is used, and whether the lightweight client device is used

Page 5 1220609 V. Description of the invention (2) Where 1a is located in this local network, users will get a transparent working environment with regional restrictions. The display protocol is used for communication between lightweight client devices and application servers. There are specific display protocols for specific software application program interfaces (APIs) to reduce bandwidth requirements. X protocol, independent computing architecture (ICA protocol) protocol, remote desktop protocol (RDP), and stateless low-level interface machine, SLIM protocol) and the like are known display protocols. The lightweight client device collects input messages transmitted by the user using the mouse and keyboard, sends these input messages to the application server for processing, and updates the response returned by the application server on the display screen. Since all applications are installed on the application server and run on it, the application server provides a centrally maintained environment, and the company's information system department can "contact" each of them without the need to In the case of a personal computer or personal computer, deploy and update applications ^ immediately, which can greatly reduce the cost of updating and deploying applications ^. = Users can also access applications and resources in a limited local area network. This can increase productivity; and because all data is managed and maintained on the server in a unified manner, security can also be improved.

In addition, the lightweight master-slave calculation mode can also improve the g and I /, ° degrees on the application server.

1220609 V. Description of the invention (3) Sharing of physical resources.

Lightweight client devices are generally low-cost, diskless, computers with display protocols in read-only memory. They only require a keyboard, monitor, serial or network interface, high-speed serial port, and bidirectional Hardware components such as parallel ports. For example, lightweight client devices include X terminals, SL I M consoles, and ICA's Windows-based terminals. By installing appropriate software that supports the display protocol, ordinary personal computers, workstations, TV set top boxes, personal digital assistants (PDAs), or mobile phones can be used as lightweight Client device. The traditional lightweight master-slave mode will be limited in use because it is applied to a single application server network, and each lightweight client device is always connected to the same application server. Since all the user's data and applications are stored on the same application server, the user can only roam in a limited area, usually in a local network, and this application server is connected to This is the only way to provide users with a transparent work environment on this local area network.

Only when the lightweight client devices are connected to the same application server can users transparently access their own files and applications. In addition, since the response time is determined by the network bandwidth and the load of the application server, the ideal response time can only be achieved when the lightweight client device is connected to the same local network as the application server. However, this would further limit the number of lightweight client devices used.

Page 7 1220609 V. Description of the invention (4) Will make, = ^ Ϊ The disadvantages and inconvenience of the client-side master-slave system come from such restrictions as # 杲: stored in the same application server: Required item f: The local network to which this application server belongs. She / he may need some environment settings? The application server in the main area, and; moreover, the root network may be unfamiliar to users # ie f .1 it ^ ^ '', all user-specific data must have a very large Storage capacity, while the parent application server charges a very large bandwidth. a In the process of shellfish transmission, a user who works for a multinational company opens her / his office in California. 、,,,, λ. The user has to encounter some questions. ^ If you try to use Λ Gennen ^ Use The server, the user should be connected to the response time in California. Xiao Za encountered a long network that was almost intolerable. In other cases, there are different users' data. Use t; + system, and we may try to complete each but complete all. On the application server, the information of the user of the child's clothes is usually: the feasibility of this method is not satisfactory. Assume that a company owns: The disks of the parent users allow more than 10,000 users to use the complete copy of the user's data: 'One should: 0 ° 2. Then, if you want to X 100 MB, it is the same as Guxin's clothing 15 needs to allocate 10,000 in addition to huge disk space;: f ,, = GB of disk storage space 丨 Use a considerable network bandwidth. For example: the user's data will account for iL10 〇〇〇〇 v 1〇 MR, for example, updating a 10-rib file will result in a total of /, 0, 00 x 1 0 ° = 100 GB of data in all application servers

1220609 V. Description of the invention (5) Transmission (if the read-one-write-all method is used) „Attention, in the above example, it is assumed that the application is completely copied in all Application server, so the application itself is not calculated. Therefore, from the above description, it is necessary to overcome the shortcomings of the traditional lightweight master-slave model. Brief description of the invention The present invention discloses an innovative lightweight master-slave calculation. Mode, called multiple-application-server thin-client / server

SyStem > MAS TC / S system for short), this multi-application server lightweight system (MAS TC / S system, system) provides a lightweight client-side device in the domain :: when a transparent working environment. The multi-application server of the present invention can easily replace the client-side master-slave system, and it can also be widely used in many areas, such as the office services of multinational companies. Eye-catching and novel Internet services Lightweight users with multiple application servers

Components: ..., having a majority = system including several server-finding protocols, and file eight = server-based network, local area network-based network. The display protocol is the same as the name display protocol, such as the X protocol, the standard i used by the slave architecture

Protocol; application server looks for protocol help, RDP protocol, and SL support for client device identification i

1220609 V. Description of the invention (6) Applicable feeders suitable for connection; and the standard decentralized system includes the functions of the traditional file decentralized system and further enhancements, including the intelligent prefetchirig mechanism and the pre-fetching convention (appointed prefetching) mechanism. The results of the examples show that the multiple client master-slave system of the present invention is provided in a wide area network to serve: a practical infrastructure for households. Service-oriented automatic application Detailed description of the invention Transparent work environment Decentralized system is a whole. The present invention provides a transparent majority of users who can roam a wide range of server users in multiple environments. It is expected that the best ones will be tested by the application to the real area network: the use is never heavy, and the application should be used separately. In other words, the entire system is considered: when the combination of 2 independent components, it is considered to be transparent work. Two servo f lightweight master-slave (MAS Tc / S) system, so that users regardless of whether it is connected to a The same qualitative work two: an application server, when she / he, she / he will not be V; "and then the answer is: 'The user will experience the essence \\ which one is connected to Use the same location to connect to: the same work environment is free, even if this server is a lightweight user: f domain network. It is pre-fetched by the transparent work environment server of the master-slave system. It must be all-the user ’s server recently cried, and the appropriate application server is better, the multiple application server

1220609 1220609 V. Description of the invention (7) The operation interface window provided by the lightweight client-side master-slave system, and the application 9 makes it necessary to specify, for example, the interface deviates from the general and accessible resources. Location is transparent and where on the WAN-= environment, including regardless of use :, user operation :: use: 'substantially the same user preferences using software, etc., guarantee = users can get a familiar working circle ;! The real f phase is' displayed on the user interface two. Same demand The superscript is not currently connected to which application server it is connected to, nor is it a definition of a transparent working environment. °° Lu, the transparent working environment has the following forms: Ming · Can use the same operation to access the area and the remote Ming can access resources but do not know their location. , Mobile transparency, poor sources, and user terminals move within the WAN, but do not affect user operations. According to the present invention, the user can log in to the system with the same account name and password not only from the local area network, but also from a wide area, and from different locations on the road. There is no need to manually set the environment, and substantially the same files, Applications, styles, and preferences, as well as work interfaces, and this is what we call a transparent work environment. Examples of systems that can maintain a transparent working environment in a local area network include

Sun ’s NFS + NIS, NOVell Netware, and Micr〇s〇ft:

Windows NT; however, the transparency of their work environment does not apply to wide area networks.

1220609 V. Description of the invention (8) Lightweight client-side master-slave system of multiple application servers (MAS TC / S system. The light-weight client-side master-slave system of multiple application servers of the present invention includes the following main components' and please refer to the figure 2 Cooperate with detailed description: The application-server discovery protocol 21 enables a lightweight client device 2a to find an appropriate application server located in a network 22 with a plurality of application servers;

The display protocol 23 enables the lightweight client device 2a and the application server to communicate with each other; and the file decentralization system 24 provides a transparent working environment so that no matter whether the user is connected to this network 2 with multiple application servers Any application server in 2 will experience substantially the same working environment. Note that the components 2 1 to 24 shown in Fig. 2 are for illustrative purposes, so the connection and function between them may not be expressed in detail.

The display protocol 2 3 in the lightweight client-server master-slave system of the multiple application server may be the same as the display protocol in the traditional lightweight master-slave computing mode, such as X protocol (X protocol), independent computing architecture (independent computing architecture, ICA protocol), remote desktop protocol (RDP), and stateless Iow-ievei interface machine (SLIM protocol). Therefore, the lightweight client devices used in the traditional lightweight master-slave computing mode can be used in the multiple application server lightweight client master-slave system of the present invention, such as an X terminal

IMII Page 12 1220609 V. Description of the invention (9) (X terminal), SLIM console (SLIM console), ICA's windows-based terminal, personal computer, workstation, TV table Set (TV set top box), personal digital assistant (PDA), or mobile phone. As shown in FIG. 2, the network 22 having a plurality of application servers includes a plurality of application servers 2d, 2e, 2f, 2g, and 2h. This network 22 with many application servers may be a wide area network, or even the Internet. Assume a situation to illustrate how this MAS TC / S system works. In Figure 2, a user is usually connected to the application server 2d to obtain the most efficient and convenient service, and all user data and broadcasts are stored in this server 2d; when the user wants When leaving the local network to which the application server 2d belongs, and going to other regions, the TC / S system works as follows: When the user uses a lightweight client device 2a to connect to a network with a plurality of application servers 22 At the time, the application server looks for the protocol 2 1 to help the lightweight client device 2 a find the most suitable application server 2h. This appropriate application server 2h is usually located in the same local area network as the lightweight client device 2a. "So" the lightweight client device 2 & can get the fastest service without being limited by the transmission rate of the network. In one embodiment, a redirection server 2b containing a database 2c of all available application server data in the network 22 assists the lightweight client device 2a to find the appropriate application server 2h. When the lightweight client device 2a is connected to the appropriate application server 2h, the two communicate with each other through the display protocol 2 3, and the file

1220609 V. Description of the invention (ίο) The decentralized system 24 is used by Vera. Fig. 3 shows the transparent, multi-application environment of the present invention. (MAS TC / S) method Step 15: Lightweight client-side master-slave system device is connected to a feeder with a plurality of applications: J: 3a 'lightweight user; In step 3b 'Appropriate use of client-side device connection < the most suitable lightweight client-side device in the network is directed to connect to this device. : ί Feeder; and in step 3d, the file is properly applied to the servo-a transparent working environment, that is, the advance; the device is appropriately applied to the server to provide a transparent working ring. It is expected that this system is connected to a network with a large number of application servers: Medium: 2 users will experience substantially the same working environment. Application server ΆΛ ^ ΆΜFinder looking for cooperation ^ Although a user tries to use When a lightweight client device is connected to a server, the application server search protocol is used to help identify the most suitable application server in a network that hosts several application servers. There are two types of application server search Protocol: (1) Multicast in search of invention (mult icast discovery) protocol: lightweight client device performs a multicast broadcast to find an application server with multiple specific group names or preset group names; or (2) unicast discovery ) Protocol: Every search for an application server published by Zhuo Yedan X client device, $ 2 or more of a database containing all application server data

Page 14 1220609 V. Description of the invention (11) server, and the application server of this light-weight client-side device, in addition to the position and status, the load of the server determines which one of the steps shown in Figure 4 The cloth thinner steering system of the steering server is a bulk system of the present invention, which has a lightweight user system for accessing and installing a large amount of materials or file recovery costs. Measure the position of the client device, tell & which is the most suitable application server, and guide the lightweight connection to the most suitable application feeder. Better I, most suitable: The device is the one closest to the lightweight client device— :. =: And ::: i ΐ According to the layout of the application server in the network = pin out the most suitable application server; for example, application server a:: = adlng status) can be considered by the people to consider the K-best B application server. / Send a search to identify the appropriate application. The server broadcasts a lightweight client device. Publishes the application. Searching for an application. == ++ a turn to the server; and in step 4b, the station = the location of the used / end device in the network. Available applications 0, states, and identify the most suitable application server. :: 2 Use the server to achieve a transparent working environment in the file system of the client-server master-slave system. In a wide area network, it may be: server ’, which means that all users’ resources: • have an application server, derived storage and communication end host;:, and it is difficult to really do it.纟 This multi-application servo is always heavy: in the second system, * there is an efficient file fetching, and the better of this file dispersing system must have a 1U Prefetching mechanism, which can predict the use of 1220609 V. Invention Description (12) __ Information needs of the individual. The functions of the system of the present invention are additionally done; the n system includes the work of dispersing the traditional broadcasts of a user; ;; =: a strong mechanism. 1 · Using to remove # 拉 ^ The two brothers need the following types of information: various; * ^, or preference: including the window manager's records and

Log files for various applications. JJ 2 · User's respect · E-mail, Clerical Office ^ Crying person will have personal files, such as 袅, Yi Wan Xuan Er w, spread sheet, chart and multimedia files. 3. The application teaches you to switch (々 co〇de). · The code of various application programs (binary of these three types of information oblique v ^. In the following two cases of planting: the type exists in the application records of the ancestral server and the user ’s record; "Data" is used to collectively refer to the table, and; "the user in the domain network may go anywhere to this application server" "quasi: the device f can enter any application server, because of the service." The user's data is provided in order to provide a rapid copy of the building's data of the present invention. It is not necessary to completely and properly store the user's data. Therefore, it is necessary to === Some user's data may not be in them, these missing files, = Don't propose a solution; if the user needs some file (s) ^ 乂 A broken application server must grab this

Page 16 1220609 V. Description of the invention (13) For the traditional lightweight master-slave response time, it must comply with the two rules, where 'to achieve an acceptable connection between the application server and the server. 1) Lightweight client device and fast connection, and (2) Application servo bandwidth. For the display protocol, the load of the multiple application servo examiner of the present invention must be adequate. However, the user's information is not copied ^ j 垔 In the client-side master-slave system, because the response time is determined to be acceptable; on the server, it is necessary to consider the absence of capture: Zai = Shuer In addition to these factors, the delay caused by Shi J J Lei k is still needed. There is a fetching mechanism ... Yoya, Qi > / You demand fetching (demand fe trh i πσ, and prefetching mechanism (prefetrh; n u etching)

Chlng mechaniSm). Grab files as required. It is carried out when fetching brown cases, and pre-fetching is similar to the previous technology. Data fetching can be found in the CPU cache and the operating system's memory paging system. The data capture units in the CPU cache and paging system are cache lines and meraore pages, respectively. However, in the application server, the files are captured. According to previous research on prefetching techniques in the Chinese cache and paging system, for miss rat io 'prefetching is better than fetching on demand, because the memory access of general programs is usually Is continuous. Obviously, the memory access of the processor is different from the user's file access. First, the cache line and memory page are usually fixed in size. However, the size of the case is not fixed. Second, the case has some additional information, such as the creation date, update time, owner, and type.

Page 17 1220609 V. Description of Invention (14) and so on. When designing the appropriate prefetch mechanism in the M AS TC / S system, two additional factors must be considered: (1) a network with a majority of application servers; and, to ad Ik- .Λ iLA Φ cfe _ and (2) Requirements for a transparent working environment The present invention includes two prefetching mechanisms: smart prefetching and agreed prefetching. The detailed description is as follows: Intelligent prefetching, the main needs are as follows: 1. Immediately need the program. Need to use the intelligent prefetching mechanism. What data is the task to prefetch. Three types: System data: Required data set settings and user system work data: Unused data and application server processing usage test After the current data request in a connection period, after login, the user ’s, including The window manager records information about the main file directory to provide user-specific information during the connection. The user must '· all other cases during the connection. Those who need correction know more, and often have good ones. Both system data and work data are captured beforehand most. However, the system's but work data is unlikely to be the same. The size of the system data of the prospective user is usually not larger than 100k β compared to the data size of the work system. Yes, use the user's desk to record buildings, etc. The application environment needs to use unused data that can be surely expected. However, his main goal is to simultaneously enter the next file and use it as a file for various applications of the environment. The files that arrive are really accurate. Again, it's Xiao Xu's user base

Page 18 1220609 V. Description of the invention (15) " Therefore, 'for system data, it is usually sufficient to grab on demand' Z is that the system data is usually small and often remains unchanged. The better intelligent prefetching mechanism is to predict the work data based on the calendar information obtained in the previous connection, including access time, access operation type, 1 and building case size. The present invention provides two methods: 1. Priority prefetching: This method lists user-related files in the order of certain priorities. A file can be specified as a function of the property of the building case in the preemptive authority; for example, a file that is often taken by a child and the size of the building case should have a higher priority. 2. Prefetching based on access pattern (access_pattern_based Prefetching): This method dynamically prefetches the file according to the user's current file request, and the user's most frequent access pattern. For example, when a user asks to open a file, he predicts with certain probability which files will be required next, and these files are candidates for prefetching. There are several techniques that can be applied to intelligent prefetching, such as data mining, neural network, artificial intelligence, and fuzzy theory. The present invention develops a comprehensive and different method based on data mining technology for prefetching according to the access pattern, which will be described below. When discussing how to predict the next file access related to the current file 4 ’The application server finds answers to the following questions:

1220609 V. Description of the invention (16) Which files will be accessed in the unit time of Θ at least Θ U% 9 °; A and 3 are the limits specified by the user. " To answer this question, you must formulate.栲 安 左 告 ， / 贝 追縱 The most frequently appearing file access type is the eight-file access type. The helmet returns to the right country A. ("graph)"-...,-, a directed acyclic graph (directed acyclic graph) Edge (fl f2): 1 "The node in the file is a file, and the ^ connected to the file indicates that after accessing the file f 1, it often hangs / follows the file ί 2 after a short period of time. Such a graph is called Temporal graph ^ graph). In any two eaves cases in the temporal graph, there are two types: f0U〇Wed or overlapped. If there is a path on the L graph connected by f1 To ί 2, f 2 is said to follow f 1, otherwise ff 2% is overlapping. In fact, a file access instance can also be represented by a time-evil map. For example, referring to the file access example in Figure 5a, The horizontal axis represents time, and each line represents the elapsed time from opening to closing a file. Figure 5b shows the relationship between invoking and invoking (inv〇cati〇n). Among them F 1 calls F 2 and F 3, and then F 3 calls F 5 and F 6. Because F 2 and F 3 are called by F 1 and their opening time is very close, we classify F 2 and F 3 as overlapping relationships. Although both ^^ and! ^ Are called by F3, F5 follows F5 because F5 is turned on much earlier than F6. The corresponding temporal diagram is shown in Figure 5c, where the dashed lines indicate the overlapping relationship. Regarding how to find frequently-occurring tense maps or data explorations in a given archive access history, please refer to the work of C.-P · Wei et al. (C.-P. Wei, S · -Y. Hwang, W. -S · Yang · Mining Frequent Temporal Patterns in Process Databases; Proc. Of the 10 'th International Workshop on Information Technologies

Page 20 1220609 V. Description of the Invention (17) and Systems (WITSOO); Brisbane, Australia, 2000). Each edge (fi, fj) on the temporal graph is accompanied by a pair of time values (ti, value pair) (//, σ), where // and σ represent the distribution of duration of the opening time of π and fj, respectively. ) Means and standard deviations. These time values can be used to calculate the likelihood of access to a building over time. For example, if the probability of fi in (fi, fj) is 30%, and the duration is a normal distribution, we can say that the # + σ unit time after accessing fi has 30% X 84.13 % Probability fj will be accessed, of which 84 · 13% is derived (X is the normal score

Cloth, the average value ", the number of variations σ2, and Φ (ζ); [μ2 / 2). ^ yjln) Under Algorithm 1 lists the algorithms used to find the files that answer the above questions. Algorithm 1: Prefetch algorithm based on access pattern

/ * find the set of files that may be subsequently accessed after the current data request within thenext ㊀ unitsoftimewitha, probabi 1 ityofat least s% 氺 / 1. · Find the set T of temporal graphs with no edges incident on f; 2. · Return- Set 2 0

Page 211220609 V. Description of the invention (18) 3. For each frequent temporal graph in TA Find the path with the largest value on d 2 / is an edge in the path, where (//], σ 3 ·) represents the duration distribution associated with the j'th edge. If d > Θ, continue with the next temporal graph;

B · Find the longest path. Let the path length be 1 and the supports of f and Ti be si and s2, respectively · If sl / s2 x (84.13%) < s, continue with the next temporal graph C · Add the files in Ti to Return-Set; 4. Return Return-Set > Wang Si Shang Mi's method is applicable to a certain number of frequency off-map.

If you set a larger value of θ and a smaller value of 3, you will prefetch = case :: Therefore, the file to be accessed is more likely to be: the above file transfer may reduce the network traffic The files that were needed earlier can be used to mean that there is a trade-off between the setting of the value; no need to store it at the time. #Use to go to the car, hit it. You can replace it in the Yitian case. Dan Xufang On the application server to which the user is connected. What to answer

Page 22 1220609 V. Description of the invention (19) The following question: π find out which files S2 will be accessed " in the next Θ 2 unit time with a probability of s 2%. S2 is contained for a long enough time. 2 The files that may be accessed ’are not S2 and are temporarily stored in the application server to which the user is connected is a candidate to be replaced. The method to deal with this problem can refer to Algorithm 1. Appointed Drefetching In addition to smart prefetching, in which the system attempts to determine the type of file access that often appears in the user's periodic schedule, the present invention provides another prefetching mechanism, called appointment prefetching, for users to set Prefetching requirements. The agreed prefetch mechanism specifies at least one file required by the user, and this specified file is transmitted in advance to the appropriate application server. In one embodiment, the 'user's schedule is expressed in a workf low mode, with the focus on their dataf1ow. More specifically, the timetable is modeled as a set of tasks, each of which is represented by a combination of (D, L, Fs), where D and [represent the period and location where the task will be executed, and F s represents Files needed for the mission. Consider this example: Peter works for a California-based company and is about to go to Japan to give a lecture in the company's Tokyo R & D department; in a cold lecture, 'he will use the following audits: preLd〇c, prel.ppt, and pre ^^ Cr. Peter did not bring these files to Japan, he just pre-designated a speaking task ((2002/2/3 0: 9: 0 0 ~ 200 2/2/30: 12: 00), Japan R & D, (prel.doc, prel.ppt, prel.scr)), the system of the present invention will pre-edit these files before he gives a speech in Tokyo.

1220609 V. Description of Invention (20) '-It is transmitted to the application server located in the Japanese R & D department. Just like smart prefetching, the schedule specified by agreed prefetching can be used for prefetching 'or can be used instead. By considering the size of the required file, the time and place where the task is expected to be performed, and the network bandwidth, the present system states that the system decides to transfer the file under the condition that the file must reach the correct location before the task actually takes place. Lowest cost schedule. Once the mission is over, these files will be replaced or deleted. Order example

The present invention has established an undisclosed prototype of the MAS Ding c / s system. The prototype spans three university campuses located in different cities of Taiwan: the National Normal University in Taipei (located in North Taiwan), the National University in Hsinchu, , Zhuhua University (located in Central Taiwan), and Sun Yat-sen University (located in Southern Taiwan) in Kaohsiung. The network systems of these three universities form a wide area network. The application server is performed on a Pentium PC running Linux 0S. Since each Lin-UX = workstation is equipped with a built-in X protocol, this χ protocol was chosen as a significant compromise. As for lightweight client devices, consider the following three platforms:

Lightweight client device type 1: general purpose personal computer or workstation with built-in X protocol and web browsing. Personal digital assistant (pda) for lightweight client device type two. Lightweight client device type three: JDK 1.3 applet network built-in X protocol and web browser Any other computer with a browser capable of running java pages, these are not

Page 24

Requires built-in X protocol. Ma uses a web page to find the protocol, so these three types of servers perform a single broadcast application server finder. A steering server has a database of f = client devices equipped with web browsing data. -The server includes all installed application servers. It firstly tries to connect to an application page with two client devices. As shown in Figure 6a, all the first users of the browser to visit the steering server can choose the application server that has the women's clothing listed, and choose the appropriate application servo feeder. Or let the system do it for him. / She has a lightweight client and 7b. Figure 7a shows the second feeding service, and the connection process is exemplified in Figure 7a, which has a built-in X protocol) or a second type lightweight client device (also the client device 7a). , At step (1), light), and then, at step (2), the home page of the feeder 7b (shown in Figures 6a and 7a redirects to the selected steering server 7b. The lightweight client device has a login home page, Moreover, the application server 7c, this application server 7c is equipped with the server 7c knows that it has an internal user to press the button on the webpage to let the application step (3), the application servo association, (shown in Figure 6b); finally, in In order to perform appropriate window management with the user and the user, use the X protocol to display the third 1 to communicate with the device 7a. Steps ⑴ and ⑴, turn to the connection process of the client device 7d. The selected application Feed 4f newly guides the lightweight client device, except that the steps shown in Figure 5a are almost the same. The user indicates this to the application server 7f (HW protocol 7) ( Shown in Figure 吒 1220609 V. Description of the invention (22)); then In step (3), the application server 7f sends a Java program (Applet) that imitates the X protocol and is called Xweird; finally, in step (4), the application server 7f executes an appropriate window manager using the X protocol to communicate with the 7d Xweird Java program communicates. Figure 6d shows a lightweight client screen display in operation with the built-in X protocol, while Figure 6e shows a web browser running the Xweird Java program (Applet) connected to the application server Lightweight client screens in the operation of the server. This month's multi-application server lightweight master-slave (MAS, C / S) quarterly system provides second-class services, and also the office automation of multinational companies The above detailed description is for the purpose of clearly describing but not limiting the scope and spirit of the present invention, and various changes made under the scope of God [: within the scope of the essence disclosed by Tuoyue. Covered

1220609 Schematic illustration Figure 1 illustrates a thin-client / server calculation mode; ® 2 examples tf A multiple application server lightweight master-slave (MAS TC / S) architecture of the present invention; Figure 3 Example The flowchart of the steps of the lightweight client master-slave system (MAS TC / S) method of the multi-application server of the present invention; FIG. 4 illustrates the step flow of using a unicast lookup to identify an appropriate application server. Figure;

Figures 5a to 5c show examples of prefetching according to the access type; Figures 6a to 6e illustrate an embodiment of a lightweight client master-slave system of a multiple application server according to the present invention; and Figures 7a and 7b illustrate lightweight The connection process between the client device and the application server.

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Claims (1)

1220609 VI. Scope of Patent Application 1. A method for roaming a lightweight client over a wide area network, comprising the steps of: connecting a lightweight client device to a network with a plurality of application servers; identifying that the application has a plurality of applications An appropriate application server in the server's network; directing the lightweight client device to connect to the appropriate application server; and Prefetching a user's data to the appropriate application server to provide a transparent working environment, so that the user will experience whether the user is connected to any application server in the network with a plurality of application servers To essentially the same working environment. 2. The method according to item 1 of the patent application scope, wherein the step of identifying the appropriate application server is achieved by the lightweight client device performing a multicast broadcast to the application server. 3. The method according to item 1 of the patent application scope, wherein the step of identifying the appropriate application server includes the steps of: the lightweight client device issues a unicast search to find a suitable application server to a redirect server; and The steering server identifies the appropriate application server. 4. The method of claim 3, wherein the steering server identifies the appropriate application server based on the location of the lightweight client device. 5. The method of claim 3, wherein the steering server identifies the appropriate application server based on the layout and status of the application server located in the network. Page 28 1220609 6. Scope of Patent Application 6. For the method of the first scope of patent application, the prefetching step includes a smart prefetching step. 7. The method of claim 1 in the patent scope, wherein the prefetching step includes an agreed prefetching step. 8. The method of claim 6 in which the smart prefetch step is prefetched according to priority. 9. The method according to item 6 of the patent application, wherein the smart prefetching step is prefetching according to a user's access pattern. 10. The method according to item 1 of the scope of patent application, wherein the lightweight client device is an X terminal, a SLIM console, an ICA window-based terminal, a personal computer, a workstation, a television desktop, or a personal computer. Digital assistant, or mobile phone. 11. A multi-application server lightweight client master-slave system including; an application server looking for a protocol to make a lightweight client device recognize an appropriate one located in a network with a plurality of application servers An application server; a display protocol enabling the lightweight client device to communicate with the application server; and A file decentralized system provides a transparent working environment so that no matter if a user is connected to any application server in the network having a plurality of application servers, the user will experience substantially the same working environment. 1 2. The system according to item 11 of the patent application scope, wherein the application server search protocol is a multiple broadcast search protocol in which the lightweight client device Page 29 1220609 VI. Scope of Patent Application Perform a multicast broadcast for the application server. 13 3. The system according to item 11 of the scope of patent application, wherein the application server search protocol is a unicast search protocol, in which each application server search issued by the lightweight client device is transmitted to a Steering server. 1 4. The system of item 13 in the scope of patent application, wherein the steering server is equipped with a database containing information of the application server located in the network. 1 5. The system according to item 13 of the patent application scope, wherein the steering server identifies the appropriate application server based on the location of the lightweight client device. 1 6. The system according to item 13 of the scope of patent application, wherein the steering server identifies the appropriate application server according to the layout and status of the application server located in the network, and guides the lightweight client The device is connected to the appropriate application server. 1 7. The system according to item 11 of the patent application scope, wherein the file decentralization system includes a prefetch mechanism. 18. The system of claim 17 in the scope of patent application, wherein the prefetch mechanism includes a smart prefetch mechanism. 19. The system according to item 17 of the scope of patent application, wherein the prefetch mechanism includes an agreed prefetch mechanism. 20 • The system according to item 18 of the patent application scope, wherein the smart prefetch mechanism includes a prefetch mechanism based on priority. 2 1. The system according to item 18 of the scope of patent application, wherein the smart prefetching mechanism Page 30 1220609 6. Scope of Patent Application ------ " " ~ Contains a prefetch mechanism based on the access type. 2 2 For example, the system for applying for patent No. 20, wherein the priority prefetching mechanism determines the priority of prefetching according to the access frequency and size of the case. 23. The system according to item 21 of the patent application scope, wherein the prefetch mechanism based on the access pattern predicts the next audit access based on the previous file access pattern. 2 4 · The system of item 19 in the scope of patent application, wherein the agreed prefetch mechanism specifies at least one file to be transmitted. 25 • If the system of item 19 in the scope of patent application, the agreed prefetch mechanism specifies a task, including the period and location where the task is performed, and includes at least one file required for the task. 26. If the system of item 11 in the scope of patent application, wherein the lightweight client device is an X terminal, SLIM console, ICA window-based terminal, personal computer, workstation, TV desktop, personal Digital assistant, or mobile phone. / 2 7 · If the system of the 11th in the scope of patent application, the display protocol is χ protocol, ICA protocol, remote desktop computer protocol, or SLim protocol