Patent Publication Number: US-8539536-B2

Title: Fragmentation of a file for instant access

Description:
This application is a divisional of U.S. application Ser. No. 11/076,214, filed Mar. 9, 2005, now U.S. Pat. No. 7,937,379 which is incorporated by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present invention is generally related to multimedia delivery over the Internet. Particularly, the present invention is related to techniques, when properly combined, for providing instantaneous media-on-demand (MOD) including services, systems and methods for the same. Further, the present invention is related to techniques for providing a dynamic library of many titles from which a user can select and instantly play back. 
     2. Description of the Related Art 
     Whether it is an elder telling a story by the fire or a family sitting in front of the television during dinner, humans have an innate need to hear stories and to be entertained. It is unbelievable how many televisions and/or radios each household has. In fact, it is estimated that every household has 2.3 televisions and that people watch television an average of five (5) hours per day. These statistics and human propensities motivate cable providers, satellite providers, video rental companies, Blockbuster Inc., NetFlix.com, etc. to invest millions of dollars to offer videos, television and movie broadcasts, premium movie channels, pay-per-view, etc. to customers. 
     Traditionally, each television viewer was satisfied to have four (4) or five (5) television channels offering a few shows and to go to the cinema for more exciting movie content. However, today&#39;s audiences have become more demanding, expecting so much more from television at home, including a large variety of more sophisticated dramas, comedies, adventures, horrors, etc. To satisfy this demand, the majority of television viewers subscribe to cable or satellite services, the basic service alone offering significantly more channels and premium broadcasts than regular television. 
     Still, customers remain unsatisfied. In response, cable and satellite services offer movie channel subscriptions. Each movie channel offers a limited number of relatively new releases of movie broadcasts at pre-selected times. A viewer can review movie lists and movie schedules, and plan to watch selected movies when they are offered. If the viewer turns on the television at the right time, the viewer can watch the movie from the beginning. Otherwise, the viewer may have to watch the movie starting from some other point. Alternatively, the viewer can record movies to watch at times more convenient to the viewer (whether using digital video recorders such as that offered by TiVo Inc. or traditional VCRs). Since the number of movies offered by these movie channels are limited, more disciplined viewers may record all desirable movies currently being provided and have to wait until additional titles come available. Since the number of movies offered on movie channels is limited and since the movies start at irregular times, movie channels do not effectively satisfy current customer demand. 
     Customer appeal of “video on demand” is well known. Generally, true video on demand can be characterized as instantaneous viewing of a movie (or other content) which may be selected from a list of preferably all movies available. Ideally, a server or set of servers will store all movies, will enable customers to select movies, and will stream the movies to the consumers while the customers view the movies without network interruption. However, given the many shortcomings of today&#39;s technology and network-related infrastructure, true video on demand is currently unavailable to the general public. Communication capacity and speed in satellite, cable and DSL networks are insufficient, unreliable, unpredictable and inconsistent. Because of the insufficient and inconsistent communication capacity and speed, if true video on demand were available, viewers on a system of today would have to settle for unwanted pauses and other erratic behavior. True video on demand will likely be unavailable to the general public for many years, available only after faster and significantly more reliable and predictable communication channels (e.g., fiber optics) are deployed and faster computing is developed. 
     In limited circumstances, true VOD is offered today using specialized, reliable networks capable of delivering and maintaining high capacity and speed. Cable “On Demand” is one such service. On Demand provides the ability to instantly download movies for playback, but only if the user is connected to a high speed digital network and if the service provider can support VOD. This service is not available over traditional broadband connections. 
     Referring now to  FIG. 1 , there shows a video delivery system  100  that is used for delivering video services over a network. The video delivery system  100  includes a video server  102  that is sometimes referred to as a head-end. Through a data network  104 , the video server  102  can provide continuous, scheduled and video-on-demand (VOD) services to respective client machines  106 - 1 ,  106 - 2 , . . .  106 - n  (i.e., its subscribers). Hence, the system  100  is a typical client-server architecture with one server  102  serving a plurality of client machines  106 - 1 ,  106 - 2 , . . .  106 - n . The server  102  is further coupled to a media storage device  112  that may be configured to store various media files (e.g., movies or news footage). The media storage device  112  must be on-line and must store and supply titles scheduled or demanded for delivery to any of the client machines  106 - 1 ,  106 - 2 , . . .  106 - n.    
     To ensure quality of service (QoS), the bandwidth requirement of the network path (e.g.,  108 - 1 ,  108 - 2 , . . .  108 - n ) to each of the client machines  106 - 1 ,  106 - 2 , . . .  106 - n  has to be sufficient. However, as the number of the subscribers continues to increase, the demand on the bandwidth of the backbone network path  110  increases linearly, and the overall cost of the system  100  increases considerably at the same time. If the server has a fixed bandwidth limit and system support capability, an increase in the number of subscribers beyond a certain threshold will result in slower transfer of data to clients. In other words, the transmission of the video data over the network  104  to the subscribers via the client machines  106 - 1 ,  106 - 2 , . . .  106 - n  is no longer guaranteed. When the video data is not received in a client machine on time, the display of the video data may fail or at least become jittery. 
     To alleviate such loading problem to the video server  102 , a video delivery system often employs multiple video servers, perhaps in multiple locations. Each of the video servers, similar to the video server  102 , is configured to support a limited number of subscribers. Whenever the number of subscribers goes beyond the capacity of a video server or the bandwidth thereof, an additional video server needs to be deployed or additional bandwidth needs to be allocated. Subsequently, overall costs go up considerably when more subscribers sign up with the video delivery system  100 . 
     As a simple solution to the video-on-demand limitations, cable and satellite providers offer pay-per-view, namely, a limited number of newer releases starting on average every half hour for about the price of a video rental. Even with pay-per-view, a customer has to select a movie from a limited set, and still has to wait until the broadcast begins. Further, in cases where the set-top box does not support two-way communication with the service provider, the customer has to inconveniently telephone a service to order the selected movie. Pay-per-view is a feeble solution to true video on demand. 
     Several cable and internet companies are considering other alternatives to true video on demand. One of the better alternative systems of today enables a viewer to select, order, download and view a movie. However, because of slow download speeds and considerable movie size, the viewer has to wait significant time, e.g., one (1) to two (2) hours, for the movie to download. Although in many ways better than pay-per-view, this option is still far from ideal. The solution makes customers wait a long time before receiving the movie, fails to give consumers immediate gratification, and fails to take advantage of impulsive nature of many purchasers. 
     Satellite providers specifically will have difficulty providing true video on demand or current alternatives because satellite communication offers no return path, i.e., offers only one-way communication from the satellite provider to the customer, and because satellite bandwidth which is sufficient for broadcast (i.e. point-to-multipoint) is insufficient for point-to-point communication. At this time, customers have no way to peruse movie options, request a movie, etc. without some two-way mode of communication. Because of the limited capabilities of satellite networks, satellite providers are at a substantial disadvantage to cable providers who can offer cable, internet broadband, voice over IP, and other network services. 
     Companies such as Blockbuster Inc. and Netflix, Inc. have created business models that attempt to give greater movie options to customers. However, Blockbuster requires customers to get off the sofa, get dressed, go to a hopefully local business establishment, select a movie (which is often unavailable), and return home before being able to start the movie. Netflix allows a customer to order movies from extensive lists, but mails the requested movies using traditional post. Customers have to wait at least several days before a requested movie is received. These two models do not offer anything “on demand.” 
     There, thus, is a great need for an instantaneous VOD system that allows users to select a desired title among a sizable library and view the ordered title instantaneously. 
     SUMMARY 
     This section is for the purpose of summarizing some aspects of embodiments of the present invention and to briefly introduce some preferred embodiments. Simplifications or omissions in this section as well as the title and the abstract of this disclosure may be made to avoid obscuring the purpose of the section, the title and the abstract. Such simplifications or omissions are not intended to limit the scope of the present invention. 
     Broadly speaking, embodiments of the invention relate to techniques for providing media services over data networks. The techniques described herein are related to each other and each is believed independently novel in the art. The disclosed techniques may be performed alone or in any combination to provide a novel and unobvious system or a portion of a system. It should be understood that the techniques in combination yield an equally independently novel combination as well, even if combined in their broadest sense; i.e. with less than the specific manner in which each of the techniques has been reduced to practice. 
     Embodiments of the present invention relate to various techniques for providing media services over data networks. According to one aspect, some of the techniques, when properly combined, can provide an instantaneous media-on-demand system, and process and method for the same. Significantly different from the prior art systems in which media services are rendered at a central server or servers, embodiments of the present invention utilize individual devices on a network to supply each other with needed sources in pieces to render required services. As a result, the loading pressure on a server is distributed into the network. 
     According to another aspect of the invention, a system provides a library with a significant number of titles from which a user may select and order a title whenever desired and play back the title fairly instantly by accessing a beginning portion of a file pertaining to the title. The beginning portion of data is locally cached while the remaining portion of the data is supplied by other designated devices. The library is updated dynamically with releases (e.g., new or popular titles). 
     According to still another aspect of the present invention, a file pertaining to a title is fragmented into a header and several tails or segments. The header is a continuous portion of the file while the segments are respective parts of the remaining portion of the file. The header is seeded substantially in all boxes, and none or at least one of the segments are distributed in each of the boxes in service. When a title is ordered, the header is instantly played back while the segments, if not locally available, are streamed in or continuously fetched respectively from other boxes that have the segments. Data from the segments being concurrently fetched is multiplexed together with data from segments cached locally, if any, to recover the remaining portion of the file and continue playback of the title. 
     According to still another aspect of the present invention, a large file is fragmented intelligently and the segments are so distributed as to best utilize the network bandwidth and maximize quality of service (QoS). The header size and the number of segments are computed or determined periodically in accordance with the required transmission rate of the title, the minimum available network speeds, etc. 
     According to still another aspect of the present invention, a library in each of the boxes in service is updated synchronously or asynchronously. Any release to update the library is performed by propagating data chunks by a gossip protocol to all boxes in service. A proper release package is then recovered in each box from the received data chunk to update the library. In a case in which a service provider is provided with a high bandwidth broadcasting or multicasting capability, a release fragmented into a header and several segments is transmitted to all boxes that are respectively configured to receive a proper release package to update the library. 
     According to still another aspect of the present invention, boxes either newly installed or put back onto the network after a period of time are updated efficiently, e.g., in a shortest possible time, to start providing services. An original library in such a box is updated with the most demanded titles first or the least amount of data possible so that the box may be in condition sooner to not only fulfill orders for the most demanded titles but also provide needed data to other boxes. Depending on implementation, the updating of the original library in a box may be carried out by receiving data chunks by a gossip protocol from other boxes that collectively have the latest titles or receiving proper release packages from a service provider via a broadcasting or multicasting infrastructure. 
     According to still another aspect of the present invention, backup boxes are provided to support boxes designated to provide data to an ordering box such that all data being transported among boxes is not delayed or interrupted. Should one of the boxes providing the data to the ordering box under-perform (e.g., due to operational issues in the box or undesirable network performance), a backup box may be launched to replace or assist the underperforming box and to continue the supply of data to the ordering box. Other aspects of the invention will become apparent and appreciated by those skilled in the art from the detailed description herein. 
     Embodiments of the invention may be implemented in numerous ways, including a method, system, device, or a computer readable medium. Several embodiments of the invention are discussed below. In one embodiment, the invention provides a method for providing media-on-demand services over a network, the method comprises receiving a request from an ordering box, the request including an order of a title in a library; and identifying one or more boxes to provide distributed objects pertaining to the title to the ordering box, wherein the ordering box proceeds with a playback of a residing object pertaining the title while downloading the distributed objects from the one or more boxes. 
     In another embodiment, the invention provides a method for providing a viewing mechanism of all titles in a library in a box. The method comprises enabling selection of a title from a library of titles in a box, generating a request when one of the titles is selected, the request including title information, transmitting the request over a network to a server configured to formulate a response, the response including source information identifying one or more boxes to provide one or more distributed objects pertaining to the ordered title, initiating a playback of a residing object in the box pertaining to the ordered title, receiving the one or more distributed objects from the one or more boxes as one or more streams of data, a portion of which is received during playback of the residing object, and initiating a playback of the one or more streams of data together with any residing objects pertaining to the ordered title, if any, as soon as the playback of the residing object is finished. 
     In still another embodiment, the invention provides a system for providing media-on-demand services over a network. The system comprises a plurality of boxes, respectively coupled to a network, each box associated with a user and providing a library of titles, each of the boxes including a storage space allowing a plurality of headers and a plurality of segments to reside therein, each of the boxes configured to provide a request including title selection information; and a server coupled to the network and configured to provide a response to a request from one of the boxes (“an ordering box” hereafter), the response including source information identifying a set of the boxes designed to provide respective distributed segments pertaining to the title to the ordering box, wherein, in responding to the response, the ordering box initiates playback of the header pertaining to the selected title while downloading one or more distributed segments from the set of the boxes. 
     In still another embodiment, the invention provides a system for managing objects distributed in a network. The system comprises a plurality of boxes, respectively coupled to the network, each associated with a user and providing a library of titles, each of the titles represented by a header and a number of segments, each of the boxes including a storage space to locally cache the header, and none, or one or more of the segments for each of the titles; and a computing device configured to provide a response after receiving a request from one of the boxes (“an ordering box” hereinafter), the request including an order of one of the titles, the response including source information identifying a set of supplying boxes that are designated to provide missing segments pertaining to the title, if not all of the segments are locally cached in the ordering box. In general, the library is partitioned into a number of groups or bands, one of the bands (a “top band” hereinafter) including some of the titles that are most demanded, and another one of the bands (a “low band” hereinafter) including some of the titles that are least demanded. In one case, the number of segments for the titles in the top band is greater than the number of segments for the titles in the low band, leading to more distributed copies for each of the titles in the top band than for titles in the low band. 
     In still another embodiment, the invention provides a method for fragmenting a file pertaining to a title, the method comprising: dividing the file into a sequence of data blocks, the sequence of data blocks partitioned into a first portion and a second portion; forming a header from the data blocks in the first portion, the data blocks in the header being consecutive; and forming N segments, each of the N segments including some of the data blocks in the second portion, with the data blocks in each of the N segments being nonconsecutive, wherein N is a finite integer greater than 1. The file is a collection of data together with auxiliary data, if there is such auxiliary data. The header is locally cached in each box in service as a residing object, and M of the N segments are stored in a box, wherein the value of M differs from title to title and box to box, and 0≦M≦N. 
     In still another embodiment, the invention provides a method for keeping a library dynamically updated. The method comprises dividing a file pertaining to a title into a sequence of data chunks, wherein the title is included in a release to update the library in each box in service, designating an initial set of seeding boxes to receive the data chunks collectively, each of the seeding boxes receiving at least some of the data chunks, and causing each of the seeding boxes to propagate at least some or all of the received data chunks to a set of the boxes, wherein each of the set of the boxes is caused to recursively propagate its received data chunks to other boxes chosen to continue spreading of some or all of the received data chunks among the boxes till each of the boxes in service has received a designated portion of the data chunks. Essentially, each box receives what it is designated to receive. The method further comprises causing each of the boxes to recover the header and none, or one or more of the segments from the some or all of the received data chunks, and subsequently updating the library therein. 
     In still another embodiment, the invention provides a method for updating contents in newly installed devices, the method comprises determining a number of outdated titles in a library when a box newly present in a system offering media services is detected; determining a corresponding number of missing titles to add into the library and to retire the outdated titles from the library; causing the box to initially retrieve data pertaining to relatively new titles in the set of missing titles so that the box is ready for servicing an order of one of the relatively new titles; and keeping the box retrieving data pertaining to the remaining missing titles till the box is fully updated. In one case, the box retrieves a header for each of the relatively new titles, and then retrieves one of several segments for each of them. In another case, the box retrieves a header and one of several segments for each of the relatively new titles in an order of declining popularity of the titles. 
     In still another embodiment, the invention provides a method for transporting data in a distributed environment. The method comprises determining whether a communication session has been established with each of boxes designated to supply needed data segments in accordance with source information provided by a computing device over a network, and downloading concurrently the needed data segments respectively from the designated boxes only after the communication session has been successfully established with each of the designated boxes, wherein each of the needed data segments includes a plurality of data blocks sampled from a sequence of data blocks representing a file. 
     In yet another embodiment, the invention provides a method for keeping a library dynamically updated, the method comprises preparing a release in a data package, the release including at least a title to update the library; and transmitting the data package via a transmission infrastructure to boxes in service, wherein each of the boxes is configured to locally cache at least a portion of the data package, and not every one of the boxes caches an identical portion of the data package. Depending on implementation, the transmission infrastructure may be capable of broadcasting or multicasting. The data package includes a header and several segments for the title. The portion of the data package locally cached in the each of the boxes includes the header and none, or one or more of the segments. Alternatively, the data package includes a plurality of release packages, each including the header and none, or one or more of the segments. 
     Accordingly one of the objects of the present inventions is to provide techniques that, when combined properly, can be used effectively to provide an Instantaneous media-on-demand system. 
     Other objects, features, and advantages of the present invention will become apparent upon examining the following detailed description of an embodiment thereof, taken in conjunction with the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1  shows a video delivery system that is commonly used for delivering video services over a network, also referred to as a server-and-client architecture; 
         FIG. 2A  shows a configuration of a distributed network system, in accordance with an embodiment of the present invention; 
         FIG. 2B , according to one embodiment, shows a file organized or fragmented into a header and four segments; 
         FIG. 2C  shows a file pertaining to a title comprising one header and four segments, assuming a situation in which a box locally stores the header and receives the four segments from four other boxes to continue a playback of the title; 
         FIG. 2D  shows a data stream representing a file, a beginning portion of which being allocated as a header and a remaining portion being decimated into four individual segments; 
         FIG. 2E  shows a flowchart or process of, in accordance with one embodiment, fragmenting a file for distribution to a plurality of boxes; 
         FIG. 3A  shows one exemplary popularity classification of titles in a library within a limited storage space in a box; 
         FIG. 3B  shows another exemplary popularity classification of titles in a library within a limited storage space in a box; 
         FIG. 3C  shows an exemplary banding scheme in accordance with the popularity of the titles in a library; 
         FIG. 3D  shows corresponding dependency of each title in a band for a continuous playback in accordance with a banding shown in  FIG. 3C ; 
         FIG. 3E  shows a flowchart or process of classifying a library of many titles for instant access according to one embodiment; 
         FIG. 3F  shows a flowchart or process of updating a library in a box according to one embodiment; 
         FIG. 4A  shows a diagram of updating, synchronously or asynchronously, a library in all boxes in service according to one embodiment; 
         FIG. 4B  shows a flowchart or process of seeding a release in boxes in service according to one embodiment; 
         FIG. 4C  shows an exemplary situation in which a service provider is provided with an infrastructure of high bandwidth broadcasting capability; 
         FIG. 4D  shows a exemplary flowchart or process of seeding a release in boxes in service for a configuration in which the bandwidth for broadcasting or multicasting is sufficient; 
         FIG. 5A  shows progressive changes to a library in a new box, according to one embodiment; 
         FIG. 5B  shows an exemplary situation in which three new boxes are added into the system; 
         FIG. 5C  shows a flowchart or process of updating a library in a box that has not been online for a period of time, and consequently has an obsolete library therein; 
         FIG. 6A  shows one exemplary implementation of a server according to the present invention; 
         FIG. 6B  shows an exemplary map illustrating how a library of 5000 titles is distributed across N boxes; 
         FIG. 6C  shows example source information as a table including an IP address (e.g., IPA1) for each of the four boxes that are designated to supply segments for an ordered title; 
         FIG. 6D  shows exemplary source information with backup boxes in a table that includes a backup identifier (shown as an IP address) for each of the designated boxes; 
         FIG. 6E  shows one embodiment in which an ordering box is being supported by three designated boxes, from which three respective segments pertaining to an ordered title are respectively provided to the ordering box, wherein the three designated boxes are respectively backed up by three other boxes; 
         FIG. 6F  shows another embodiment in which an ordering box is being supported by three designated boxes, wherein the three designated boxes are respectively backed up by three other boxes that at the same time backup other designated boxes supporting other ordering boxes; 
         FIG. 6G  shows a flowchart or process of starting an instant playback of a selection (i.e., a title) in a library; 
         FIG. 7A  shows one exemplary implementation of a box that may correspond to any one of the boxes of  FIG. 2A ; 
         FIG. 7B  and  FIG. 7C  collectively show a flowchart or process of starting an instant playback of a selection (i.e., a title) according to one embodiment of the present invention; 
         FIG. 7D  shows the multiplexing of four streams of segments to generate a data stream for playback as soon as a first portion being played is finished according to one embodiment of the present invention; 
         FIG. 7E  shows a flowchart or process of prioritizing tasks in a box according to one embodiment of the present invention; and 
         FIG. 8  shows an architecture in which many aspects of the present invention are equally applied thereto. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the invention relate to various techniques for providing media services over data networks. Some of the techniques, when properly combined, may provide instantaneous media-on-demand. One embodiment may provide a dynamic library with a significant number of titles from which a user can select and order for playback fairly instantly. To facilitate instant playback, a file pertaining to a title may be fragmented into a header and several segments (a.k.a., tails). In one embodiment, the header is seeded in all boxes and the segments are distributed within the network to the boxes according to a scheme. When a title is ordered, the header can be instantly played back while the segments, if not locally available, can be streamed in from supporting boxes. Data from the segments being concurrently fetched can be multiplexed with locally cached segments, if any, to recover the remaining portion of the file and continue playback of the ordered title. 
     In addition, in one embodiment, a library in each of the boxes in service may be updated synchronously or asynchronously by propagating data chunks, e.g., using a gossip protocol, to all boxes in service. Any boxes that are either newly installed or put back in the system after a period of time can be updated in a short time to start providing services. Other possible features, benefits and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
     In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. The present invention may be practiced without these specific details. The description and representation herein are the means used by those experienced or skilled in the art to effectively convey the substance of their work to others skilled in the art. In other instances, well-known methods, procedures, components, and circuitry have not been described in detail since they are already well understood and to avoid unnecessarily obscuring aspects of the present invention. 
     Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one implementation of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, the order of blocks in process, flowcharts or functional diagrams representing one or more embodiments do not inherently indicate any particular order nor imply limitations in the invention. 
     For convenience, definitions for some terms are provided below. It should be noted that the definitions are to facilitate the understanding and description of the present invention according to one embodiment. The definitions may appear to include limitations with respect to the embodiment. However, the actual meaning of the terms may have applicability beyond such embodiment. 
     Media or video—used interchangeably herein, indicates multimedia data, a collection of which with other possible auxiliary data is referred to as a file. Because such a file is typically large in size, it is often compressed for storage or transmission in accordance with a commonly used standard (e.g., H.264, MPEG-1, MPEG-2, or MPEG-4). Examples of a video may include, but are not limited to, movies, games, footage, a collection of documentary or multimedia data. 
     Local device, computer, machine or, simply, box—used interchangeably herein, is a computing device typically used by a user to access a media file. Such a client machine may operate independently or with another device. Examples of the client machine include a set-top box, a computing device (such as a desktop, a laptop, a PDA, a telephone, a tablet PC, etc.), a television with network capability and a network storage device. 
     Residing object and distributed object are relative terms. When a file is divided into several pieces or segments, some of the segments may be distributed remotely in other boxes. These distributed segments are referred to as “distributed objects.” The header and other segments cached locally are referred to as “residing objects” or “resident objects.” 
     Server, server device, server computer, or server machine—used interchangeably herein, is a computing device, typically located remotely from local boxes. Depending on implementation, a server herein may mean a stand-alone computer or a cluster of two or more computers configured to deliver the server operations described herein. 
     Embodiments of the present invention are discussed herein with reference to  FIGS. 2A-8 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only as the invention extends beyond these limited embodiments. 
     One embodiment of the present invention is related to a technique for delivering video services over a data network that is not adversely affected by a growing number of users. In one embodiment, the more users there are, the better the performance delivered by the system or process. 
       FIG. 2A  shows an exemplary configuration  200  of a distributed network system  100 , in accordance with an embodiment of the present invention. It will be appreciated that the entire network may comprise multiple of such network systems  100 , for example, one for each box of a particular type, size, content, etc. 
     A server  202 , presumably managed and/or populated by a service provider, is configured to handle the delivery of video (or multimedia) services to users via local machines or boxes  206 - 1 ,  206 - 2 , . . .  206 - n . Different from the video server  102  of  FIG. 1  that delivers video data to a subscriber upon receiving a request therefrom, the server  202  is not responsible for delivering the content in response to a request from a user, and instead is configured to provide source information as to where and how to retrieve at least some of the content from other boxes. In other words, the server  102  of  FIG. 1  requires the media storage device  112  to provide the content when any of the client machines  106 - 1 ,  106 - 2 , . . .  106 - n  is being serviced, while the server  202  does not need a media storage device to provide the content. Instead, some of the boxes  206 - 1 ,  206 - 2 , . . .  206 - n  are respectively configured to supply part or all of the content to each other. 
     According to one embodiment, when fulfilling a request from a local machine or a box (e.g.,  206 - 1 ), communication between the server  202  and the box  206 - 1  over the network paths  208 - 1  and  210  may be limited to small-scale requests and responses (e.g., of small size and very short). A server response to a request from a box may include source information (e.g., identifiers), authorization information and security information. Using the response from the server  202 , the box may be activated to begin playback of a title (e.g.,  207 - 1 ). Substantially at the same time, the box may initiate one or more requests to other boxes (e.g.,  206 - 2  and  206 - n ) in accordance with the source identifiers to request subsequent portions of the title (e.g.,  207 - 2  and  207 - n ). Assuming proper authorization, the requesting box receives the subsequent portions of the data concurrently from the other boxes. Because of box-to-box communication of content, the bandwidth requirement for box-to-server communications over the network paths  208 - 1  and  210  is kept low and typically short in duration. In the event there are a large number of user boxes issuing playback requests substantially at the same time, the bandwidth of the backbone path  210  should be sufficient to avoid noticeable or burdensome delay. 
     The contents available in a library offered in any of the boxes  206 - 1 ,  206 - 2 , . . .  206 - n  are originally provided by one or more content providers. Examples of the content providers include satellite receivers, television relay stations, analog or digital broadcasting station, movie studios and Internet sites. Depending on implementation, the contents may be initially received or originated in the server  202 . Instead of maintaining and managing the content in a large storage device, the server  202  is configured to distribute the content or files to a plurality of local machines registered with the server  202 . The boxes  206 - 1 ,  206 - 2 , . . .  206 - n  shown in  FIG. 2A  are examples of local machines in service. Unless there is a need for a backup copy, the server  202  at any time has no need to keep a copy of the content. On the other hand, unless there is a special need to keep a complete copy of an extremely high-demand title in a box, none of the boxes in service has a complete copy of a title until an order is placed. Consequently, with embedded security in the distributed objects, some embodiments of the present invention may alleviate the concern of electronic piracy and widespread distribution (e.g., by hacking or illegal duplication). 
     For convenience, it is assumed herein that a file pertaining to a title is played back when the title is selected and ordered by a user. When an order for a title is placed, a corresponding file must be available for playback. Embodiments may enable a file, or at least a portion thereof, regardless of its size, to be accessed instantaneously. According to another embodiment, where a file is 840 Mbytes on average and a box includes a storage capacity of 300 Gbytes, a system may offer a large library of titles (e.g., 5000) for access at any time instantly. In the prior art, if the files for the titles must be stored in advance to offer instantaneous playback, the local storage of a box would have to have a capacity of 4,000 Gbytes, consequently, rendering instantaneous VOD economically impractical. 
     According to one embodiment of the present invention, only a beginning portion (referred to as a “header”) and possibly one or more tail segments of a file are locally cached in a box. Such locally cached segments are referred to as residing objects, while segments not residing locally are referred to as distributed objects. When a title is selected, the header of the corresponding file is instantly played back. During the time the header is being played, the distributed objects corresponding to the title are retrieved simultaneously from other boxes. When the header is finished, the received parts of the distributed objects being streamed in from other boxes is combined with residing objects for the title, if any, to enable continuous playback. Depending on the popularity and concurrent demand for a particular title, the number of residing objects may be increased or decreased to control the dependency of each box on other boxes for playback. Typically, the more residing objects for a title a box has, the more distributed copies of the title there are in the entire system and thus the less dependency of the ordering box on the other boxes. 
     In one embodiment, the header is always played first to ensure instant playback. However, when a box has more than one residing object for the file, the residing objects other than the header (a.k.a., resident segments) will be played together with the distributed objects (a.k.a., distributed segments) being downloaded or fetched from the other boxes. These resident and distributed segments are collectively referred to as “segments” of a file. 
     For example, in  FIG. 2A , when a user selects a title for playback from a box  206 - 1 , a header  207 - 1  of the corresponding file residing in the box  206 - 1  is instantly accessed (provided that the user has been authenticated and/or payment is settled). In this example, there may be four segments for the video file, two of which are distributed in other boxes (e.g.,  206 - 2  and  206 - n ). During the playback of the header, two distributed segments are downloaded from the other two boxes and locally buffered with the resident segments as continuing content. When the header is done, the continuing content is played back. As a result, instantaneous VOD may be realized. 
     Referring to the embodiment of  FIG. 2B , a file  220  is organized or fragmented in terms of a header portion  222  and a tail portion comprising four segments  224 . In general, the file  220  may be divided into any number of header and segment portions in consideration of a required transmission rate (e.g., related to the encoding and decoding rates for successful playback), and the minimum uploading and downloading capabilities of a network. According to one embodiment, given a required transmission rate (e.g., 1 megabit per second or 1 Mbps), the minimum uploading and downloading speeds of a network are considered to determine a number that defines the segmentation, and thus the dependency on other boxes and the support for concurrent demands of a particular title. It is assumed that a minimum uploading speed is U and a required transmission rate is D, and D/U=K&lt;k, where k is the smallest integer greater than K. In one embodiment, a file is preferably divided into a header and k segments to optimally utilize the uploading speed of U, assuming that the downloading speed is at least k times faster than the uploading speed. For example, in a POTS-based DSL network for residential areas, the required transmission is about 1.0 Mbps while the uploading speed is about 320 kbps. Hence, k=4. 
     As shown in  FIG. 2C , a file  230  comprises one header  232  and four segments  234 - 237 .  FIG. 2C  assumes a situation in which a local box stores only the header  232  and depends on four other boxes to supply the four segments  234 - 237 . Assuming that the local box  239  has a downloading speed four times the uploading speed of the other boxes, while the header  232  is being played back, the four segments can be downloaded concurrently across the network  238  as streaming into the local box  239  around the same time. 
     As also shown in  FIG. 2B , a header  232  is the beginning portion of a file while each segment is a decimated portion of the remainder of the file. In this embodiment, the data in the header is continuous, meaning the header itself can be played back (e.g., the first 15 minutes of the title), while the segment portions  234 - 237  must be present together before the tail portion of the file can be played.  FIG. 2D  shows a data stream  240  representing a file. The beginning portion of the file  240  is allocated as a header  242  and the remaining portion is divided into four “vertical” segments  247 - 250 . The segments  247 - 250  are created or formed by respectively sampling, in a decimated manner, the remaining portion of the file. 
     Depending on an exact data length of the remaining portion, the n-th data block in each of the segments  247 - 250  is four successive data blocks in the remaining portion of the file. In one embodiment, a data block comprises a chunk of data, for example, 256 Kbytes or 1 Mbyte. As shown in  FIG. 2D , the remaining portion of the data stream  240  is expressed in data blocks as follows: b11, b21, b31, b41, b12, b22, b32, b42, b13, b23, b33, b43, . . . b1n, b2n, b3n, b4n. With the decimated sampling, the four segments  247 - 250  obtained from the remaining portion can be respectively expressed as follows: 
     Segment 1={b11, b12, b13, b14 . . . }; 
     Segment 2={b21, b22, b23, b24 . . . }; 
     Segment 3={b31, b32, b33, b34 . . . }; and 
     Segment 4={b41, b42, b43, b44 . . . }. 
       FIG. 2D  shows one exemplary embodiment of fragmenting a file into a header  242  and four segments  247 - 250 . There can be other ways to fragment a file. For example, besides fragmenting a file into several “vertical” segments representing a tail portion of a file, one or more segments may be allocated to represent audio portions of the file. Typically, a movie includes several audio tracks, each for a language (e.g., English, French or Spanish). As a result, all segments are not necessarily equal in length but need to be available at the same time to support playback. This particular example illustrates that not all segments for a title must be fetched to play back the title (e.g., all segments for the video data and only one segment for one selected audio track). In another example, the file  220  can be segmented in terms of red, green, blue, and brightness values. Thus, an image can be generated even if one of the segments is missing. Of course, forming an image from red, green and brightness alone may compromise image quality. In such a case, colors may have to be estimated, possibly based on prior frames or other criteria. In general, different files may be fragmented into different numbers of segments. 
       FIG. 2E  shows a flowchart or process  260  of fragmenting a file for distribution to a plurality of boxes. The process  260  may be implemented as a method, a process, and/or a system, or in software, hardware or a combination of both. At  261 , the process  260  awaits a file to be fragmented for distribution to boxes. When such a file becomes available, at  262 , minimum uploading and downloading speeds for a network as well as a required transmission rate are obtained. In general, different networks could have different speeds. Although it is not required to have the network uploading and downloading speeds to dictate a number of fragments for the file, the knowledge of such speeds in view of the required transmission rate of the file enables the file to be fragmented to make efficient use of the network speeds (or bandwidths). 
     At  264 , the number of segments k for a file is determined with reference to a number of factors including the minimum uploading and downloading speeds obtained from  262  and a required transmission rate of data for proper display (e.g., 1 Mbit per second). In one embodiment, the actual number of segments is chosen slightly greater than k, for example k+1, provided the downloading bandwidth is sufficient (greater than the required transmission data rate). The extra segment, as will be further described below, may provide extra time to stabilize or overcome network or box instabilities. 
     The size of a file header is determined at  266 . In general, a larger header size results in fewer available titles in a library. In one embodiment, the header size is determined to last just long enough to assure receiving and playing the remaining portion (in the distributed objects) in a continuous fashion or, perhaps, may include some extra time for synchronizing the objects respectively being fetched and to manage instabilities. In another embodiment, the header size is automatically calculated as a function of a number of parameters such as the minimum network speeds in an area being serviced, and scenes that may be translated to a higher transmission rate. In still another embodiment, a header is used as a carrier to transport other information to boxes, for example, security information, and short footage of commercial information. 
     Not shown in  FIG. 2E  is an option to secure the file in its entirety. In one embodiment, the file is scrambled in accordance with an encryption scheme or by a cipher to protect the content therein, wherein the header may be independently deciphered before playback. Regardless of whether the file is encrypted or clear, it can be fragmented as is. Once the header size is determined at  266 , the header portion is readily created. At the same time, the remaining portion of the file is decimated into k segments. In another embodiment, the header and none, one or more of the k segments are distributed to each box in service. The details of determining which box is to receive the segments will be described below. In any case, the header and the segments may be secured before distribution. At  270 , a certain type of security may be embedded into the header and the segments. Depending on implementation, the header and the segments may be respectively encrypted in accordance with an encryption scheme or a cipher (e.g., Data Encryption Standard algorithm, Blowfish block cipher, Twofish cipher and RC-4) and/or protected by digital rights management (DRM). 
     At  274 , the header and the segments (i.e., respective packages) are distributed to each box in service. According to one embodiment of the present invention, the distribution is performed synchronously or asynchronously by propagating the respective packages as chunks of data from boxes to boxes, the details of which are described below. A box may be selected to receive one, more or possibly all of the segments. After  274 , the process  260  goes back to  261  for another file. 
     One embodiment may enable a dynamically updated library with a large number of titles offered to users. Each of the titles may be selected and ordered for instant playback. Given a large library, for example, of 5000 titles that are updated periodically (e.g., daily) and can be accessed anytime instantly, some of the titles may be more popular and thus demanded more often and by more users than others. To minimize possible bandwidth problems or unavailability of boxes for sourcing popular titles, the seeding of residing objects and distributed objects should be performed intelligently, e.g., according to popularity, geography, demographics, and/or like criteria. 
       FIG. 3A  shows one exemplary popularity classification of titles in a library in a limited storage space  300  in a box. For convenience, it is assumed that the storage space  300  has a capacity of 300 Gbytes and that there are 5000 titles available for instant playback. Any of the 5000 titles may be selected and instantly accessed for playback. For a VOD application, each movie on average is assumed to be about two hours. For display quality acceptable to most users, a file for a two hour movie is about 840 Mbytes in size. For a header of about 30 Mbytes, each of the four segments, assuming each file&#39;s size is close to the average, must therefore be about 203 Mbytes (i.e., (840 Mbytes−30 Mbytes)×¼). Thus, the storage space  300  must be about 240 Gbytes (i.e., 5000 titles×30 Mbytes+50 titles×2 segments×203 Mbytes+50 titles×2 segments×203 Mbytes+4900 titles×5% of the segments×203 Mbytes=240 Gbytes) to accommodate the 5000 titles for a distribution as shown in  FIG. 3A . 
     According to the embodiment of  FIG. 3A , the 5000 titles are divided into two bands, a top band  302  for those newly released or more popular titles and a low (L) band  304  for those relatively less popular titles but still demanded from time to time (e.g., “007: James Bond” or Disney movies for minors). If a library has 5000 titles, the top band  302  may be allocated to accommodate 100 titles, and the low band  304  may be allocated to accommodate the remaining 4900 titles. As new titles are released and added into the top band, the titles already in the top band  302  are either discarded or moved to the lower band  304 . In another embodiment, the top band may further be divided into two bands, a high (H) band for the latest, for example, 50 titles and a medium (M) band for the next 50 slightly older titles. 
     The allocation of an M band facilitates flexible management of the titles in the top band. It is estimated that over 70% of revenues in a movie rental business come from the titles in the top band and over 40% of the revenues from the titles in the H band. As will be further described below, the number of segments for titles in the M band may be reduced or only a percentage of the titles in the M band may be cached with one or more segments, so as to allocate more resources to update the titles in the H band quickly or reduce the dependency of the titles in the H band on other boxes. 
     In this embodiment, there are 50, 50 and 4900 titles, respectively, in the H, M, and L bands. In general, when a box has been in service long enough, each title in the top band  302  is seeded with a header and one or two corresponding segments, and each title in the L band is seeded with a header and some of the segments. As far as the number of segments per each title in the L band is concerned, only a percentage of the titles therein are seeded with one segment per each title, and those titles are typically different from one box to other box. Because the demand for a title in the top band  302  is much higher than those in the L band  304 , the percentage of segments in a box for titles in the L band may be set at a relatively small number, for example, 5%. The distribution of the segments for the titles in the L band is made in such a way that there is always at least one distributed copy of these titles in the system and more distributed segments of titles in the top band. From another perspective, if a title in the top band  302  is selected, there are more boxes that may be designated to supply the distributed segments to support the playback of the title in the ordering box, thus reducing the possibility that other boxes would be unavailable to supply the missing segments. If a title in the low band is selected, because of the relatively low popularity, it is likely that there will be sufficient distributed copies available in the network so that other boxes can be designated to supply the respective segments for playback. 
     In operation, when a title in the H band is selected in a box, two of its segments already reside in the box. Thus, only two other boxes are needed to feed the two missing segments (i.e., dependency=2). When a title in the L band is selected, in many cases, four other boxes are needed to feed the four segments (i.e., dependency=4). In other words, the popularity of a title determines the dependency of an ordering box on others. The more popular a title is, the less dependent the ordering box is on others. 
     As described above, a library is updated periodically (e.g., daily or weekly). Every time, a new title is received, the new title is typically added into the H band. In one embodiment, it is desirable to maintain a relatively fixed number of titles in the H, M and L bands, the relatively least popular title in the H band is moved to the M band while the oldest title or relatively least popular title in the M band is moved to the L band. On the other hand, it is possible, although rare, that a title in the L band or the M band is promoted to a higher band. Whenever a title is retired from the M band to the L band, the oldest or relatively least popular title in the L band may be discarded. In accordance with  FIG. 3A , whenever a title is moved from the top band  302  to the L band  304 , one or both segments from the top band  302  may be dropped depending on whether the title falls in the percentage that is designated to maintain one segment. 
     In general, there is more than one title released in a day to update a library. However, not all of the titles are necessarily new titles (i.e., for the top band), some being very popular and others being less popular. For example, a library may be updated with ten titles in a day, one newly released title in the top band and nine less popular titles in the L band. When the title is added to the top band, two corresponding segments are also added, and at the same time, a relatively old title from the top band (e.g., likely from the M band) may be discarded or moved to the L band. The relatively old title from the M band may be combined with the nine titles to be determined whether any of these ten titles fall into the percentage (e.g., 5%) for which one segment is supposed to be cached locally for a particular box. 
     In the embodiment, each box caches 5000 headers (possibly identical, possibly different, e.g., in size, possibly different in format, possibly different in security used, etc.), one per available title. These residing objects ensure that a user can begin playback instantly when a title is ordered and can continue playback long enough to start receiving the distributed objects from other boxes. To facilitate the description of the distribution of segments, the four segments are labeled respectively as 1, 2, 3 and 4. For titles in the top band  302 , there are two segments distributed locally and two segments distributed in other two boxes. As a result, there are six possible combinations of locally stored segments: (segment  1 , segment  2 ), (segment  1 , segment  3 ), (segment  1 , segment  4 ), (segment  2 , segment  3 ), (segment  2 , segment  4 ), (segment  3 , segment  4 ). These combinations are distributed fairly evenly among the boxes in service. If an ordering box has segment  1  and segment  2 , a first other box and a second other box need to be called upon to provide segment  3  and segment  4 , respectively, to the ordering box. Any box that has either segment  3  or segment  4  may be the first or the second other box. For example, a box with (segment  1 , segment  3 ) and another box with (segment  1 , segment  4 ) may be the first and second other boxes, respectively. 
     In one embodiment, boxes are classified into types. For example, there are six types of boxes, each designated for storage of one of the six combinations provided above. If there are 50 titles in the H band, besides a corresponding header in each of the boxes, the segments for each of the 50 titles are distributed according to one of the six combinations. 
     For titles in the L band, each box stores one segment of 5% of the titles. When one of the titles in the L band is ordered, that box may or may not have a segment cached locally. Accordingly, the distribution of the segments for the titles in the L band must ensure that boxes in service collectively have all segments for all the titles. In other words, there must be at least one copy in the network of each title in the L band. 
     There are a number of ways to distribute the segments for titles in the L band among the boxes in service. According to one embodiment, to facilitate the management of the distribution of the segments for the titles in the L band, the distribution of segments for titles in the H band is referenced. For example, when segment  1  and segment  2  for a title in the H band are stored locally, either segment  1  or segment  2  for a title in the L band will be stored locally (since the box need only discard one of the segments when retiring a title from the top band to the low band). Accordingly, the following management of the distribution holds: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Store locally for a 
                 If segments for titles 
               
               
                   
                 title in the L band 
                 in the H band are 
               
               
                   
                   
               
             
            
               
                   
                 segment 1 or 2 
                 segment 1 and 2 
               
               
                   
                 segment 1 or 3 
                 segment 1 and 3 
               
               
                   
                 segment 1 or 4 
                 segment 1 and 4 
               
               
                   
                 segment 2 or 3 
                 segment 2 and 3 
               
               
                   
                 segment 2 or 4 
                 segment 2 and 4 
               
               
                   
                 segment 3 or 4 
                 segment 3 and 4 
               
               
                   
                   
               
            
           
         
       
     
     The determination of which titles in the L band fall into the selected percentage for a particular box may be determined based on a number of factors. In one embodiment, the percentage is determined as a potentially randomized function of the ages or popularity of the titles. In another embodiment, the percentage is determined based on statistics of viewing behavior and a preferred language in an area or other measures that may facilitate the retrieval of distributed objects from other boxes more efficiently. In still another embodiment, the percentage is determined from a learning engine that may be embedded in a box dynamically recording some or all of the following exemplary list:
         1. the set of programs (e.g., movies) a user has been watching so far from the box;   2. the programs that user has rated (e.g., on a scale of 1 to 10) on the box;   3. the programs on a wish list created by the user for future watching; and   4. browsing activities (e.g., trailers the user has watched and the time the user has spent on reading a brief introduction for a title).       

     The learning engine may be activated to provide statistics to suggest which programs, e.g., movies are similar to the ones the user has watched (e.g., with respect to actors, directors, or genres). Accordingly, these movies are chosen to be among the percentage of the titles to have the corresponding segments. In addition, the determination of which pairs of movies are similar may be made based on what is referred to as “collaborative filtering”, namely, if many users like to watch a pair of movies, then the two movies may be considered similar. Thus, additional movies similar to those likely selected and ordered in the box may be added to the percentage of titles as well. In any case, a box may cache segments pertaining to titles that are more likely going to be selected and ordered by a user via the box. In another embodiment, each movie may be defined by certain attributes. User behavior may suggest user preferences of certain attributes. By matching preferred attributes to movie attributes, the learning engine may determine which segments for I band titles to store in each box. Also, comparisons can be made between like but different users. For example, if a first user prefers action-based movies and has previously ordered movies X, Y and Z and if a second user prefers action-based movies, the learning engine may opt to store segments for movies X, Y and Z on the second user&#39;s box. 
       FIG. 3B  shows another exemplary popularity classification of titles in a library within a limited storage space  310  in a box. One of the major differences between  FIG. 3A  and  FIG. 3B  is that the top band  302  in  FIG. 3A  retains one header and two segments for each title therein while the top band  310  in  FIG. 3B  retains one header and one segment for each title therein. 
     Contrary to  FIG. 3A  or  FIG. 3B , according to one embodiment, all boxes in service may be configured to include more than two segments for one or more titles in the H band, essentially increasing the number of distributed copies of those highly demanded titles. When a title is newly released or statistically determined popular, the boxes in service can be activated to increase the number of segments for these titles so that dependency of an ordering box on others is significantly reduced. 
       FIG. 3C  shows another exemplary banding scheme in accordance with the popularity of the titles in a library. The banding scheme divides titles in a library into multiple bands (e.g., 5 bands). The curve  320  shows A, B, C, D and E bands with the A band representing the most popular titles and the E band representing the relatively least popular titles in the library. The titles available in each of the bands may be updated periodically according to one or more measurements from, for example, demand statistics, geographic locations, a preferred language, age of the title, demographic information, or the like. Each box will store the header and all of the corresponding segments for titles in the A band (e.g., one or two newly released titles). Each box will store the header and three segments locally for titles in the B band. Each box will store the header and two segments locally for titles in the C band. Each box will store the header and one segment locally for titles in the D band. And, each box will store the header and one segment locally for a small percentage, say 5%, of titles in the E band. As a result, the dependency of each title in a band for a continuous playback as listed in a table  326  shown in  FIG. 3D  is 0, 1, 2, 3 and possibly 4, respectively. 
     For completeness, the table  326  also includes a column  328  showing exemplary statistics of demands for titles in each of the bands, namely, the demands for the titles in the band A are expected to be about 60% of the overall requests for the library. The declining demand for titles in bands B, C, D and E are illustrated as 20%, 10%, 8% and 2%. Although there may be a huge demand for a title in band A, the dependency of the ordering box on other boxes for a title in band A is zero. Therefore, orders for titles in band A can be locally fulfilled. On the other hand, the demand for titles in bands B, C, D and E progressively decreases. Accordingly, the dependency of an ordering box in bands B, C, D and E progressively increases. Distributed copies of titles in the bands B, C, D and E progressively decrease. 
     The banding scheme described above with reference to  FIGS. 3C and 3D  may be extended logically to any number of bands for a specified number of segments in accordance with the popularity of the title. For example, we may introduce a band B′ that lies between bands B and C in the previous example, with each box storing an average of 2.5 segments per title in the band. One way to create and control such an average number of segments would to let half the boxes store 2 segments and half the nodes store three. In an extreme case, each title would not only have a different number of segments, but each box may also independently determine how many segments to cache locally for each title. In general, the more popular a title is, the more segments there will be locally cached and the more distributed copies there will be available in the network. In any case, when a title in a library has no segment locally cached, there must be at least one copy of all corresponding segments in the network. Otherwise, an order for such a title could not be rendered. 
       FIG. 3E  shows a flowchart or process  360  of classifying a library of titles for instant access. The process  360  may be implemented in software, hardware or a combination of both as a method, a process, and/or a system. When the process  360  is employed in a VOD system, a file pertaining to a title may be fragmented in accordance with the process  260  of  FIG. 2E  into a header and one or more segments. At  362 , it is necessary to determine how files pertaining to the titles should be distributed, thereby defining the number of titles stored in each library. In general, the number of titles available in a library is a function of a number of factors that include the capacity of a storage space in boxes, header size, network speeds, demand, file size, required data transmission speeds, concurrency support, etc. In one embodiment, it is determined that 5000 titles may be offered in a library, each lasting for two hours on average and comprising 840 Mbytes-1 Gbyte in size. The process  260  of  FIG. 2E  may be used to determine fragmentation of the files. Once the number of the bands is determined, the process  360  goes to  364 . 
     At  364 , the titles are classified into bands. At least, two bands are used, a top band for the most popular titles (e.g., new releases) and a low band for relatively less popular titles. Depending on implementation, one or more intermediate bands may be introduced to store titles that neither fit in the top band nor the low band and to facilitate updating a library. As described above, there will be more distributed copies of titles in the top band than those in other bands to accommodate concurrent orders. In operation, the number of titles in the top band is preferably kept small to optimize the use of the storage space in a box. 
     At  366 , the number of segments for each band is determined. According to one embodiment, more segments for a title in the top band are locally cached, which translates to more distributed copies available in the network. As a result, for a more popular title, an ordering box depends less on other boxes to supply the segments needed for continuous playback of the title. On the other hand, only a percentage of titles in the low band are locally cached, which translates to fewer distributed copies available in the network. If the system is configured to include intermediate bands, the number of segments to be locally cached may decrease progressively from the top band. 
     At  368 , the process  360  determines the boxes in which to cache segments. Depending on implementation, a segment distribution scheme may be based on different factors to optimize segment caching for efficient storage and effective sourcing of titles. In one embodiment, the distribution of segments is determined based on viewing behaviors. By examining the viewing behaviors of users, it may be determined statistically which box is more likely to order a particular title. For example, users who frequently order action movies are more likely to order another action movie. When distributing segments pertaining to titles for action movies, the distribution may be orchestrated to ensure that these segments end up in boxes that are statistically more likely to order action movies. In another embodiment, distribution may be based on preferred languages. The distribution of segments pertaining to titles in a preferred language, e.g., Spanish, may be made so that such segments end up in boxes associated with boxes statistically more likely to order movies in the preferred language. 
       FIG. 3F  shows a flowchart or process  380  of updating a library in a box. The process  380  may be implemented in software, hardware or a combination of both, and as a method, a process, and/or a system. When the process  380  is employed in a VOD system, a large file pertaining to a title may be fragmented in accordance with the process  260  of  FIG. 2E  into a header and several segments. A library in each box is updated periodically or at a predetermined time. The process  380  may be used to dynamically update the library so that all boxes in service are synchronized in terms of the titles available. 
     At  382 , the process  380  awaits a release. As will be further described below, a release (comprising one or more titles) may be provided directly from a server (e.g., the server  202  of  FIG. 2A ) or propagated from other boxes. Each title in the release is fragmented into a header and a number of segments (e.g., by the process  260  of  FIG. 2E ). For a title that has been fragmented into a header and four segments, there are six different release packages that boxes may desire (for those titles that require a header and two segments): (header, segment  1 , segment  2 ), (header, segment  1 , segment  3 ), (header, segment  1 , segment  4 ), (header, segment  2 , segment  3 ), (header, segment  2 , segment  4 ), and (header, segment  3 , segment  4 ). At least one of these release packages will be received in a box. 
     In one embodiment, upon receiving a message that a release is available or data set from either the server or a box, process  380  begins. At  384 , in accordance with the release package, an appropriate band for each title in the release is determined. As described above, the title may pertain to any type (e.g., a high band or a low band). Therefore an appropriate band to accommodate the title is determined. To avoid exceeding a predefined number of titles in a band, an existing but relatively least popular title in the band is preferably retired from the band. At  386 , such relatively least popular title in the band is determined. In one embodiment, a received message pertaining to the release indicates which existing title in which band is to be discarded or moved to a lower band. At  388 , the title is added into the allocated band by receiving in the box the header and the corresponding segments (which may be none) pertaining to the title. 
     At  390 , a library list in the box is updated. Depending on implementation, the library list may be updated locally by removing the retired title and adding the new title, or an updated library list may be received. As a result, the retired title would no longer be available and the new title would be available for order. 
     Referring now to  FIG. 4A , there shows a diagram  400  of updating a library of all boxes in service. When a server (e.g., the server  202  of  FIG. 2A ) updates the library, the library in all the boxes is updated accordingly. According to one embodiment, the updating process is carried synchronously and/or asynchronously. 
     The server  402  is configured to prepare a file pertaining to the release of a title into a header and segments. One exemplary method to prepare the file is the process  260  of  FIG. 2E . For convenience, it is assumed that there are a header and four segments. Accordingly, as described above, depending on which band the release is to be put in, there may be a plurality of release packages. In operation, each of the boxes in service is configured to receive one release package. 
     Initially, the server prepares a release instruction including metadata about a release, a least popular title to be discarded from the library and/or title transfers. The instruction may describe which box gets which of the release packages and how (the package is to be received (i.e., from which other boxes). For example, the instruction could specify that boxes identified by identifiers that demonstrate certain characteristics are to receive a release package X. There may be a default instruction that applies in general to all releases, and there may be instructions tailored to specific releases as well. One of the objectives of assigning release packages to boxes may be to distribute the packages fairly evenly among all boxes in service to ensure uniform distribution of different segments. 
     The release instruction, once prepared by the server, is propagated to boxes in service either via direct communication between the server and a box, or by box-to-box propagation of the instruction via a gossip protocol, which will be described in detail below. In any case, it is assumed that each box recognizes the need for it to receive a particular release package. 
     The release is transformed into a sequence of data chunks  403  representing the header and segments for the release. A data chunk is an atomic unit of data transfer from the server to the boxes, or between two boxes. For example, each of the data chunks may be 1 Mbyte in size and uniquely identified. The sequence of data chunks  403  may represent two separate titles being propagated to the boxes to update the library. In general, each box desires a specific subset of the data chunks that make up a proper release package corresponding to that box. In addition, the release instruction itself may be represented as one or more data chunks that are to be propagated to all boxes. 
     In operation, the server  402  initiates respective communications with a set of boxes  404 - 1 ,  404 - 2 , . . .  404 - n  and provides each of them with some of the data chunks required by that box. Preferably, each data chunk is seeded into at least one of the boxes by the server  402 . The exact number of the boxes  404 - 1 ,  404 - 2 , . . .  404 - n  initially to receive the data chunks does not constrain distribution. In one embodiment, the designation of the boxes  404 - 1 ,  404 - 2 , . . .  404 - n  is fairly random. In another embodiment, the designation of the boxes  404 - 1 ,  404 - 2 , . . .  404 - n  is based on one or more of a time zone, the geographical location, an available network bandwidth, and the latency thereof, the Internet service provider for the box, etc. In any case, whenever the server  402  is idle, the server  402  can always designate different boxes to receive data chunks. 
     Each of the boxes  404 - 1 ,  404 - 2 , . . .  404 - n  is configured to spread data chunks to other boxes in service based on what is commonly referred to as a “gossip protocol,” an application-layer multicast-like protocol. It should be noted that not all of the boxes  404 - 1 ,  404 - 2 , . . . and  404 - n  have received identical data chunks. Any of the boxes  404 - 1 ,  404 - 2 , . . . and  404 - n  may start to spread a data chunk to other boxes as soon as it has received a data chunk in its entirety. In operation, the box  404 - 1  is assigned to propagate at least some of its received data chunks to boxes  406 - 1 ,  406 - 2  and  406 - 3 , communicating with one or more of these boxes simultaneously. The box  404 - 2  is assigned to propagate at least some of its received data chunks to boxes  406 - 2  and  406 - 3 . The box  406 - 2  is configured to know exactly what data chunks to get from the box  404 - 1 , the box  404 - 2 , and any other boxes configured to feed it chunks of data. Further, the box  406 - 2  is assigned to propagate at least some of its received data chunks to boxes  408 - 1 ,  408 - 2  and  408 - 3 . Note that the propagation of data is not necessarily hierarchical. For example, box  408 - 1  might send data chunks “backward” to  406 - 1 , as seen in the figure. 
     In one embodiment, data chunks are propagated only to boxes that actually desire those particular chunks in order to avoid wasteful data transmission. Moreover, wasteful data transmissions may be avoided by ensuring that a data chunk is propagated to a box only if it does not already possess that chunk and is not in the process of downloading that chunk from elsewhere. The propagation of chunks may be through synchronous protocols where all boxes participate at the same time in a coordinated fashion, or asynchronous protocols in which each box may choose when to participate and for how long in a flexible manner. For example, a box could cease participating in the downloading and propagation of chunks whenever it is busy serving a movie for an ordering box, or when the network is detected to be in a period of intense usage. The box may continuously monitor the network conditions, and adaptively rejoin the gossiping propagation when there is sufficient bandwidth available. 
     In operation, if any one of the boxes, for whatever reason, fails to accept data chunks, the box could be dropped as a supplier or a substitute box could be configured to receive and supply the data chunk. The box that missed the release may fetch the data later from one or more updated boxes. By repeatedly and recursively propagating data chunks via boxes after boxes (i.e., by pulling or pushing synchronously and/or asynchronously), eventually all boxes in service will be populated with each release (the header and designated segments of all titles to be added and the identification of titles to be removed). 
     After updating is finished, a map  409  identifying which box has which segments can be developed. By the map  409 , whenever an order is received from an ordering box, the server can designate appropriate boxes to supply the non-locally cached segments to the ordering box. Alternatively, the map  409  enables a box to obtain source information to fetch needed segments to fulfill an order. 
     When the release is not for the top band, the determination of which box to retain what segment(s) may be based on several factors such as geographic locations, time zone, viewing behaviors or a preferred language so as to maximize the efficiency of transporting the segments among the boxes when needed. 
     It should be appreciated that deletion of titles from a list of available titles may be distributed to the boxes first. That way, no box will order a title that is no longer available. Distributing title deletion instructions may be implemented using the gossip protocol discussed above or may be provided by direct box-to-server communication. 
     Referring now to  FIG. 4B , there shows a flowchart or process  410  of seeding a release to boxes in service. The process  410  may be implemented in software, hardware or a combination of both. The process  410  is particularly useful to update a directory that is maintained in multiple locations without using a centralized server. One of the possible features, advantages and benefits of the process  410  is that the directory in the multiple locations is updated synchronously and/or asynchronously by propagating an update in data chunks via locations to locations by an application-layer multicast-like gossip protocol. When the process  410  is employed in a VOD system, a library with many titles may be updated dynamically or efficiently without requiring high bandwidth to support simultaneous updating. 
     At  412 , the process awaits a release that may become available at a device (e.g., a server by a service provider) on the data network. When the release becomes available, the files pertaining to the release are prepared in a server at  414  for distribution to the boxes. The process  260  of  FIG. 2E  may be an exemplary process for fragmentation into a header and corresponding segments for each of the files. 
     At  416 , the header and segments are divided into chunks of data. At  418 , the server designates an initial set of boxes to receive at least some of the data chunks. In one embodiment, the boxes may not receive identical data chunks. Depending on implementation, the server may push respective sets of data chunks to the initial boxes or the initial boxes may pull respective set of data chunks from the server. In some embodiments, a copy of all data chunks is distributed to the initial boxes so that the initial boxes may seed the other boxes in the system without further involving the server. 
     At  420 , the process  410  determines whether any one of the boxes were unable to receive any of the data chunks. If there is a box that does not receive the data chunks, the process goes to  422  where a box that does not belong to the initial set replaces the failing one. As a result, at least one complete set of data chunks may be initially distributed synchronously or asynchronously among the set of seeding boxes. 
     The process  410  then moves to  424 , where each of the seeding boxes is configured to spread at least some of the received data chunks to one or more other boxes (e.g., another set of boxes physically nearby), each of which is configured to further spread at least some of its received data chunks to other boxes. It should be noted that any box may at the same time communicate with more than one box to collectively fetch data chunks. The process  410  then returns to  412  awaiting any other release. 
     In operation, the process  410  is not limited to updating a library one title at a time. By transforming titles into data chunks, more than one title may be spread into the system by propagating the data chunks from boxes to boxes asynchronously. Also the process  410  does not have to end before another title can be distributed. Before one release has been completely seeded in the boxes in service, another release may be made available for distribution. In operation, the process  410  is preferably started when network traffic is low, such as at midnight. Typically, the process  410  may take hours to finish. 
       FIG. 4D  shows a flowchart or process  440  of seeding a release to boxes in service for a configuration in which a service provider is provided with one or more high-bandwidth channels for broadcasting or multicasting. Such configuration may be found in a cable or satellite infrastructure that enjoys very high speed broadcasting or multicasting capability, or in a data network with multicast support. The process  410 , preferably understood in conjunction with  FIG. 4C , takes advantages of such infrastructure to update a library in boxes with one or more titles, wherein the boxes are assumed to be equipped with the receiving capability (e.g., tuners) and tuned to appropriate channel(s) for receiving the broadcast(s). Examples of such boxes include a satellite receiving box and a cable set-top box. 
     As shown in  FIG. 4C , a server  432  is coupled to a network  436  that may be a cable network (i.e., the coaxial cables or fibers as the medium) or a satellite network (i.e., the air as the transmission medium). Similar to the server  402  of  FIG. 4A , the server  432  is responsible for distributing a release. At  442 , the process  440  awaits a release. The process  440  is activated when a release become available. The titles pertaining to the release is prepared at  444  in the server  432  for distribution to the boxes. The process  260  of  FIG. 2E  is an exemplary process for fragmentation into a header and corresponding segments for each title. 
     At  446 , a release package including the header and all segments for all titles is broadcast to the network  436  at a predefined time or periodically. In accordance with an instruction that may be received from the server  432  or that may be locally configured, each box captures and caches the data in accordance with its configuration from the release at  448 . For example, a box supposed to receive a header and no segments only captures and caches the header. If a box is supposed to receive a header and two segments, the box only captures and caches the header and the two segments. 
     Since each of the boxes in service chooses appropriate data from the consolidated single release package, the library in each box is updated synchronously. In the event that some boxes are unable to update at the time of broadcast, these boxes can be updated in a next broadcast or asynchronously with other updated boxes using the process  410  of  FIG. 4B  as described above. In one embodiment, multiple channels in the cable or satellite infrastructure may be utilized to expedite the updating process by broadcasting or multicasting, for example, a respective release package in a specified channel. As described above, in one scenario, there may be six different release packages, each for one type of box. As such, a box may be configured to tune to the specific channel for its release. 
     New boxes recently placed in service or recently reconnected to a network after a lengthy period of time are collectively referred to herein as new boxes. These new boxes may be empty or include headers and segments of titles available at the time of being packaged for shipment or being unplugged from the network, but now pertaining to some titles currently available and some titles currently unavailable. During the time these new boxes were disconnected from the network, the library in active boxes will have been updated many times. As a result, the original library will be outdated. 
     It is assumed that a service provider updates a library with ten releases each day and the total number of titles in the library is 5000. If the idle time is ten days, the original library has missed one hundred releases. If the idle time is about six months, the original library in the boxes would be outdated by about 1800 releases.  FIG. 5A  shows progressive updates to a library  500  according to one embodiment. At the time of becoming a new box (being unplugged or just copied with the library before shipment), the box includes 100 titles in the top band  504  and 4900 titles in the low band  506 . For a box that has been out of service for 180 days, the library status  510  shows how outdated the box is, namely, that the library  500  has missed 1800 releases, 100 of which are the releases that in the top band  504  and 1700 of which are releases in the low band  506 . It will be appreciated that, if there is a run on stores to purchase these boxes, there will not be many titles to update. Similarly, if there is not a run on stores to purchase these boxes, then there will not be many boxes to update, even though the titles in the new boxes may be quite outdated. 
     It is commonly understood that releases decline in demand or popularity over time and eventually are put into a low band  506 . Therefore, after 180 days, there are about 1800 titles in the original library  500  that should be retired, and only 3200 titles in the original library  500  that may remain in the library  510 . In one embodiment, the 1800 titles will be retired immediately at the time the box is put into service since the network no longer supports them. 
     To update the library  510 , the box must receive the 1800 missing headers and segments corresponding to the box type and band information. To download each of the headers and corresponding segments for the 1800 releases, subject to the bandwidth of a network, it could take days, weeks or even months before the box could be used for ordering a title, which is not operationally desired. 
     In one embodiment, the process of speeding up the update of a box is achieved by dividing the top band into additional bands. For example, there may be two bands, referred to as high (H) and Medium (M) band, respectively. Each band may be assigned a number of titles, for example 50 titles in the H band and 50 titles in the M band. For convenience,  FIG. 3A  may be used as an exemplary popularity classification of titles with the H band, the M band and the L band. To reduce the time a box needs to update the library, the fetching of a large number of segments for the M band may be avoided. The rationale behind this idea is that titles in the M band are declining in popularity anyway, and will soon not need that many distributed segments in the network to support concurrent demand. Thus, for example, a new box may choose to treat the M band titles like the L band, and store one segment for only a small percentage of these titles. 
     In the same or another embodiment, a box enables the user to quickly gain access to the popular titles in the library, and soon gain access to the entire library, by fetching the headers of the missing titles before fetching the segments. It is to be noted that the user can order and play back a title so long as the header is present locally in a box; no segments need to be cached locally to enable playback, even if the title happens to be in the H band, since it will be possible to fetch the distributed segments from across the network. Therefore, a good strategy for updating a box is to give precedence to fetching headers ahead of tails, and moreover, order the sequence in which headers are fetched according to title popularity, so that the most popular titles are made immediately available. 
     In the same or another embodiment, some tail segments may be given higher precedence over some headers, so that some segments are quickly received by a box and it can start acting as a useful supplier of segments and serve demand from other boxes. It may be appreciated that there are many different ways to determine which segments are given precedence over which headers, depending on the trade-off that needs to be struck between how quickly the user needs to be given access to the entire library, and how critical it is that the user&#39;s box becomes a useful supplier that bears some of the system&#39;s load. We describe one particular embodiment of precedence choices involving headers and segments below. 
     According to one embodiment, a new box begins by downloading a header and one corresponding segment for each of the 50 titles in the H band; this data may be fetched from other boxes that have the corresponding headers and respective segments for the 50 titles. The library status  512  shows the desired status of the H band being updated on Day 1 (assuming that the entire update of the H band finishes in a day). It may be appreciated that there may be several ways to update the titles in the H band. In one embodiment, the headers for the H band starting from the most demanded title are progressively fetched first, followed by the segments for each title in the H band. In another embodiment, a header and corresponding segment for each title in the H band, starting from the most demanded title, are progressively fetched first. 
     After the 50 titles in the H band are nearly updated (in the case where each H band title requires two local segments, each title still has one missing segment at this stage), the 50 titles in the M band are to be updated next. However, during the updating of the 50 titles in the H band, other titles are being added into the library by dynamic updating. As a result, there may be less than 50 titles in the M band to be updated because one or more titles may have been retired from the H band into the M band (shown by arrows in the figure). In one embodiment, a header for each of the titles in the M band is fetched from other boxes in service and one segment for only 5% of the titles in the M band is fetched. In another embodiment, only the headers for the M band title may be fetched, leaving the segments to be fetched later on. The intermediate status of the M band can be better appreciated in  FIG. 3A  to explain why there are zero, one and two segments for the titles in the M band. 
     After day 1+X (see library status  514 ), where X indicates the time required to update the H and M bands, depending on the network speeds, a certain number of the titles from the H band may be retired into the M band, and at the same time, a corresponding number of the titles in the M band may be retired into the L band. If the library is organized progressively in terms of ages of the titles in the library, it may be appreciated that the original 100 titles in the library status  502  have been shifted and that, although there are 1700 titles in the L band that should have been updated, the retirements from the top band  504  has in fact reduced the actual number of the titles to be updated. At this time, the headers for titles in the L band are fetched continuously, until headers are received for all missing titles. Finally, all missing segments are fetched as well, for titles in the H, M and L bands. Library status  516  depicts the final state of the library after the updating process is completed. 
       FIG. 5B  shows a situation  530  in which three boxes  532 - 534  have just been added into the system. After the three boxes  532 - 534  have registered respectively with a server  536  with their respective identifiers and/or IP addresses and library statuses, the server  536  returns with information on what these boxes have missed in the past and how to get updated, for example, where to fetch the missing titles. The situation  530  shows that the box  532  shall initially fetch the missing titles (e.g., a header, or perhaps a corresponding segment) from a group of boxes  537 - 540 , and the boxes  533  and  534  shall initially fetch the missing headers from a group of boxes  543  and  544 , respectively. It is noted that in operation a box (i.e.,  532 ) is configured to dynamically switch from boxes to boxes to fetch corresponding headers and/or segments. 
     It is assumed that the three boxes  532 - 534  are initially updated with one header and one segment for each of the titles in the top band (i.e., the H band). In operation, the three boxes  532 - 534  can be candidates to start serving others (e.g., for titles in the H band). In  FIG. 5B , an ordering box  542  is placing an order for a title in the top band. It is also assumed that the title pertains to a file that has a header and four segments, two of which reside in the ordering box  542 . Therefore the ordering box  542  needs to fetch the other two missing segments. While the header for the title is being played, the ordering box  542  may get the missing segments from any two of the boxes  532 - 534 , provided that each of them has one of the two missing segments and not all of them have an identical one of the two missing segments. As the box groups  537 - 540 ,  543  and  544  are busy to update the boxes  532 - 534 , the boxes  532 - 534  start to serve others as soon as segments for the releases in the H band become available. Hence, it may be appreciated that the maximum sustainable concurrency for titles in the H band remains unchanged. Moreover, it will be appreciated that playback support for newly released titles may be diverted to the new boxes, since the new boxes can only support playback of the new releases. This could reduce traffic problems significantly and improve the maximum concurrency sustainable for a title in any band. 
     Referring now to  FIG. 5C , there shows a flowchart or process  550  of updating a library in a box that has not been online for a period of time, perhaps due to its being on store shelves for a long period after it has been manufactured. The process  550  may be implemented in software, hardware or a combination of both as a method, a process, and/or a system. The process  550  awaits any new boxes that are coupled to a network at  552 . The process  550  is activated when a new box is detected in the network or a server is notified of the presence of a new box. In one embodiment, the new box, once powered and connected to the network, is configured to automatically inform and/or register with a server associated with a service provider. The box may send a notification including its identifier and an IP address thereof, and perhaps the date/time the box was last updated. 
     At  553 , the process  550  detects whether the library in the box needs to be updated in accordance with a record. There are cases that the library in a box does not need to be updated; for example, if the box was powered off for a short period of time, it may not have missed any new content. In one embodiment, the server determines whether the library needs to be updated in accordance with the status of the box. If there is no need to update the library, the process  550  goes back to  552  waiting for another new box. If it is determined that the library needs to be updated, the process goes to  554 . 
     At  554 , the set of outdated titles in the library, and the set of releases missed in the past, or currently missing from the box, either due to the box being off-line or due to storage errors, needs to be determined. To synchronize with the updated library in other boxes, the outdated titles are flagged as not being accessible any more (even if the data may still be available in the box). The process  550  then proceeds with the updating of the library at  556 . As described above, the library is initially updated with the headers of the high band titles so that the box may accept orders of these titles and support the orders of other boxes for these titles. In operation, as soon as a header is cached locally, the box is in condition to fulfill an order for a title associated with the header. For the high band titles, the box is configured at  556  to fetch a header, or a header and a corresponding segment for each of these titles from other boxes. One of the exemplary mechanisms to fetch the headers or the segments is by the application-layer multicast-like gossip protocol as described above. 
     The system may be designed to require that each box store a header and only one segment of the high band titles. Alternatively, the system may be designed to require that each box store a header and more than one segment of the high band titles. In any case, the box is ready to serve other boxes for fulfilling an order or updating a library. Further, it will be appreciated that the responsibility for updating a new box with the new titles may be diverted to newer boxes since they will only be able to assist with updating new titles. 
     While the titles in the top band are being updated, the process  550  checks whether there is any release from the server. If there is a release at  558 , depending on where the release fits in the library, an appropriate title in the library may be affected. In one embodiment, the library is virtually divided into a number of high, intermediate and low bands. If a title in the release is supposed to be in the high band, a relatively less popular title in the high band is retired to a next lower band, which essentially reduces the actual number of the titles originally determined at  554 . If there is no release or the release only includes not the most demanded titles, the process  550  continues between  556  and  562  until the titles in the high band are updated. In operation, the titles in each band are successively and progressively retired from one band to a lower band in terms of popularity and/or age. For convenience, it is assumed that three bands, H, M and L bands are used. 
     Now the process  550  goes to  564  to fetch a header for all the titles in the M and L bands and additionally a corresponding segment for a small percentage of the titles in the M band and L band. In one embodiment, 5% of the titles in the M band for now have a segment and 5% of the titles in the L band also have a segment. As a result, updating the library avoids stopping the box from providing services. In any case, every time a title is retired from the H band to the M band, the corresponding segment thereof is simply moved to the M band. Any other segment may be discarded per the system design. And, when a title is moved to the L band, the segment for the title may be retained in the L band or discarded depending on whether this title falls into the percentage of the titles that are designated for this box. In the case of controlling a fixed number of titles and preserving the local storage, a corresponding title in the L band, typically the most unpopular, is discarded or overwritten. It may be appreciated that the discarding of segments can be done lazily when the box begins to run out of storage space, and can be avoided if there is more storage space available. 
     At  566 , the process  550  continues to fetch segments for titles in the H band and/or M band without affecting the box from servicing the users or other boxes. It is described that there is a case in which there are two segments for a title in the H band. It is recalled that at  556 , only one of the segments has been fetched so as to minimize the time to have the box ready for servicing users or other boxes. Accordingly, another segment may be fetched now at  566 . Likewise, every title in the M band is supposed to have at least one segment but only 5% of the titles therein have a segment thus far. Accordingly, the respective corresponding segments may be fetched from other boxes without preventing the box from servicing the user or other boxes. 
     Not directly shown in  FIG. 5C , operations similar to  559  are inherently included in  564  and  566 , respectively. Further, some of the process  550  can be carried out any time in a day, preferably when the traffic in the network is low. When choosing other boxes to supply the needed data to update the library, these boxes may be decided or switched from time to time to take advantage of the conditions in the network, geographic locality, sustained bandwidth realized between the supplier and the receiver, etc. as well as the conditions of the boxes themselves. 
     It may also be understood that the availability of a high-bandwidth broadcast or multicast channel, such as those available via Cable or Satellite networks or through IP multicast, can be exploited to speed up the process of updating a box, just as described earlier in the context of seeding new movies. Broadcast channels may be devoted to transmission of the latest releases, perhaps giving precedence to those titles in highest demand. New boxes may then tune to the appropriate channel(s) to quickly receive headers and segments for the titles they are missing. 
     Referring now to  FIG. 6A , there shows one exemplary implementation of a server  600 . The server  600  may correspond with the server  102  of  FIG. 1A , and may be a single computing device or a cluster of computers. The sever  600  includes a server module  602  and an interface  604 . In general, the server module  602  is loaded in a memory and executed by one or more processors (not shown) to perform its operations. In application, the server  600  may be operated by a service provider or an enterprise to provide media services to users. 
     The server  600  also includes a delivery agent  606  that facilitates communications between a content or source provider  608  and the server  600 . Depending on implementation, the source provider  608  may include, but may not be limited to, a content receiver, a content producer, and a movie publisher. The delivery agent  606  is provided to ensure contents are received properly from the source provider  608 . Depending on how the content is received, the delivery agent  606  may be implemented in various forms. For example, a movie publisher releases movies to a service provider operating the server  600 . The movies may be transported securely to the server  600 , in which case the delivery agent  606  is a secure transmission medium. In another example, the content may be transported by satellite, in which case, the delivery agent  606  may be a satellite receiver. In still another example in which a corporation desires to advertise its products or services via the server  600  to a plurality of users, the corporation may deliver a commercial video to the server  600  via the internet. Accordingly, the delivery agent  606  is part of the Internet or a local network and provides a necessary interface (e.g., TCP/IP) to facilitate data communication between the server  600  and the Internet. Other examples are also possible. 
     For efficiency, the server  600  may include or be coupled to a transcoder  609  that is provided to convert source files in various formats into an acceptable format which is understood by client boxes. Typically, a video source provided by a content provider could be high-definition video signals, DVDs, film, etc. If that format is not a desired format for the server  600 , the transcoder  609  is activated to convert such source to the acceptable format (e.g., MPEG-2 or MPEG-4). As described above, the source provider  608  may provide many types of sources. With the transcoder  609  or an appropriate device with similar functions, the server  600  can receive any type of sources and distribute them to users for fees or for information. 
     The server  600  includes another interface  604  that facilitates data communication between the server  600  and a plurality of boxes in service over a data network  611 , wherein the server  600  may be located remotely with respect to the boxes. The network  611  can be part of a large network including the Internet, the public switch telephone network (PSTN), a private network, or a wireless network. The network  611  may use one or more different transmission media, such as telephone lines, cables, fibers or air (wireless). An exemplary communication protocol used for communications between the server  600  and the boxes is TCP/IP. 
     As shown in  FIG. 6A , the server module  602  includes a plurality of functional engines or modules that are configured to work cooperatively with each other. Not every module listed in the server module  602  of  FIG. 6A  must be employed in practice. Depending on actual implementation or needs, the modules may be selectively deployed. 
     User management module  610  is configured to manage subscribers or users. It facilitates addition, deletion or updating of accounts pertaining to all users subscribing to or desiring to receive media services from the service provider. The user management module  610  also manages payment settlement for all the accounts. In one embodiment, each account is billed for a fixed monthly fee that allows unlimited access to the media service. In another embodiment, each account is updated or charged whenever an order for a title in a library provided by the service provider is placed. 
     Content management module  612  manages all content that may be provided to the users. As described above, the content is organized in the form of headers and segments. These objects are distributed among the boxes in service. The content management module  612  is configured to manage the distribution of these objects. By accessing the content management module  612 , an operator may control directly how to distribute objects related to titles in the library and get mapping information on what is available and how and where these objects are distributed.  FIG. 6B  shows an exemplary map  630  illustrating how a library of 5000 titles is distributed across N boxes. Column  632  lists all boxes in service. Each box is assigned a unique identifier for identification. Information in the column  632  may be viewed as the identifiers for the boxes in service. For example, box  1  is assigned a unique identifier of “Box  1 ” or a sequence of alphanumeric characters. 
     Column  634  lists a corresponding IP address for each of the boxes listed in column  632 . Column  636  lists the headers for all titles in the library. Column  638  lists what segments for title 1  are residing in each of the boxes, assuming title 1  is required to have two segments cached in each box. Column  640  lists what segment for title 2  is residing in each of the boxes, assuming title 2  is required to have one segment cached in each of the boxes. Column  642  lists what segment for title 5000  is in a selected set of boxes, assuming title 5000  is required to have one segment in these selected boxes. As a result, all objects (i.e., headers or segments) in a box may be uniquely addressed for uploading to another box or playback of an ordered title locally. 
     Delivery management module  614  is configured to respond to an order received from an ordering box. Working with the content management module  612 , the delivery management module  614  creates, in responding to the order, a response that includes source information, authentication information and security information. An example of the source information is graphically illustrated as a table  650  in  FIG. 6C  or a table  652  in  FIG. 6D . The table  650  includes an IP address (e.g., IPA1) for each of the four boxes that are designated to supply the segments for an ordered title. The authentication information authenticates the ordering box for secured communications with other boxes. The security information facilitates decryption of any data for playback of the title. The response may further include an IP address identifying the ordering box and instructions as to what segments to retrieve from other boxes. Upon receiving the response, the ordering box allows the header corresponding to a title (assumed in the L band) being selected to be played, and at the same time or substantially soon after, the ordering box initiates four respective requests in accordance with the response received from the server. It is understood that each of the requests includes an IP address of one of the four boxes. When each of the four boxes receives one of the requests, the requested segment is released or uploaded to the ordering box. 
     Network management module  616  is provided to monitor the status of each of the boxes in service. In one application, the network management module  616  is configured to receive an address of a box. In many cases, a box is assigned a dynamic address by an Internet service provider that may be changed from time to time. To ensure each and every box in service is in contact with the server  600 , whenever the IP address of a box is changed for whatever reason, the new IP address thereof must be notified to the server in time. In one embodiment, each of the boxes is configured to send or receive a short message event triggered or periodically to or from the server such that the network management module  616  updates, if necessary, the IP address for the box that has changed its IP address. On the other end, the network management module  616  is configured to send a short message to each of the boxes for a short response. If a box is out of operation (e.g., powered off or malfunctioning), the network management module  616  is thus notified immediately and updates the delivery management module  614  that may exclude the box out of designation for providing segments for an ordering box. Similarly, if a box is already supplying a segment for a movie order, the network management module may keep the delivery management module informed of the box&#39;s availability status for supplying a segment for another order. 
     Seeding management module  618  may also be referred to as a library management module. The seeding management module  618  is responsible for updating the library in each box. Whenever there is a release, the seeding management module  618  ensures proper seeding of the release into the boxes. In a situation in which the release is a newly released movie and likely in high demand, the seeding management module  618  causes a header and at least one of the segments of the file pertaining to the release to reside in each of the boxes. In another situation in which the release is not a newly released movie but may be popular in demand, the seeding management module  618  causes a header and possibly one of the segments of the file pertaining to the release to reside in each of the boxes. In still another situation in which the release is a classic title and is relatively less popular in demand, the seeding management module  618  causes a header to reside in each of the boxes and the segments to reside in a selected group of the boxes in the network. In yet another situation in which there is a new box just coupled to the network, the network monitoring management  616  is configured to notify the seeding management module  618  of the status of the box. Depending on the status of the existing library in the box, the seeding management module  618  determines what is missing in the library and provides instructions to the box how to update the library from other boxes. 
     Security management module  620  is provided to secure the objects distributed across the boxes in service. In one embodiment, the security management module  620  is configured to authenticate a user associated with an ordering box and provide one or more security keys and authentication information to the ordering box after the user is authenticated and/or a payment for the order is settled. The security keys, once in an ordering box, may facilitate the decryption of the header and/or segments. The authentication information allows the ordering box to communicate with the designated boxes to fetch needed segments for the playback of the title. In another embodiment, the security management module  620  works in conjunction with the content management module  612  or the seeding management module  618  to encrypt all objects (headers and/or segments) before they are distributed across the boxes in service. In still another embodiment, the security management module  620  provides digital rights management (DRM) of all contents that are distributed as objects across all boxes in service. In still another embodiment, the security management module  620  may remove small portions from a title&#39;s file before it is broken into segments and distributed across boxes. When a box orders a title, these portions of the file are supplied directly by the server, perhaps as part of the server response, improving security by ensuring that the title cannot be fully constructed without the active participation of the server. 
     Commercial information management module  622  is provided to manage commercial information intended to display to users whenever appropriate. Examples of such information may include, but not be limited to, advertisements, special offers, movie trailers and public broadcasts. Such information may be superimposed onto a small part of a display showing a movie, displayed during intervals between two movies, or beginning of showing a movie, or simply requested by a user. Depending on implementation, such information may be appended to a header pertaining to a release or distributed independently according to one or more factors that include geographical locations of the boxes, viewing behaviors or preferred languages of the users. 
     Source provider management module  624  is provided to manage distribution of any fees paid by users for using any distributed contents originated by providers. Depending on implementation, the source provider management module  624  may be configured to share payments with respective content providers on daily, weekly or monthly basis via the delivery agent  606  or provide financial outlook or statistics of titles in the library being offered. 
     In further reference to the delivery management module  614  in  FIG. 6A , according to one embodiment, the delivery management module  614  is configured to prevent a situation in which one or more of designated boxes become suddenly unavailable or slow down to continue the supply of the required segments to an ordering box. The source information in a response to the ordering box includes backup information for each of the designated boxes.  FIG. 6D  shows exemplary source information with backup boxes in a table  652  that includes a backup identifier (shown as an IP address) for each of the designated boxes. Should one of the boxes fail to respond to the request for a segment from the ordering box or the segment cannot be received correctly, the backup IP address is immediately called upon to switch to the corresponding backup box that is available to provide or continue to provide a segment that the originally designated box fails to provide. 
     For completeness,  FIG. 6E  shows one embodiment in which an ordering box  654  is being supported by three designated boxes  655 - 657  to receive three respective segments pertaining to a title being ordered in the box  654 . Each of the boxes  655 - 657  is provided with a backup box that has a corresponding identical segment. Specifically, the box  655  is supported by a backup box  658 , the box  656  is supported by a backup box  659 , and the box  657  is supported by a backup box  660 . While a header for the ordered title is played in the ordering box, the three distributed objects are being fetched from the boxes  655 - 657 . If, for some reason, the box  656  refuses to continue providing the segment, the backup box  659  is activated to replace the box  656  to continue providing the segment. In one embodiment, the backup box  659  is configured to join the box  656  to conjointly supply the segment to the box  654  (e.g., each supplying a different portion of the same segment). 
       FIG. 6F  shows another embodiment in which an ordering box  670  is being supported by three designated boxes  671 - 673  to receive three respective segments pertaining to a title being ordered in the box  670 . In operation, the breakdown of an ordering box, for whatever reason it may be, is rare, and the breakdown of several boxes at exactly the same time is even rarer. Therefore the three backup boxes  674 - 676  for the three designated boxes  671 - 673  may also be designed as the backup boxes to other designated boxes supplying segments.  FIG. 6F  shows an ordering box  677  being supplied by two designated boxes  679  and  680  while an ordering box  678  is being supplied by three designated boxes  682 - 684 . To ensure the respective fetching processes are carried out successfully, each of the designated boxes is supported by a backup box, in which case, the two designated boxes  679  and  680  are being backed up by the boxes  674  and  675  and the three designated boxes  682 - 684  are being backed up by the boxes  674 - 676 . In the event one of the backup boxes  674 - 676  becoming an active box, the server  600  may immediately designate another box in the field to be the backup box. 
     Referring now to  FIG. 6G , there shows a flowchart or process  686  of starting an instant playback of a selection (i.e., a title) in a library. The process  686  may be implemented in software, hardware or a combination of both as a method, a process, and/or a system. Preferably, the process  686  is executed in a computing device designated as a server facilitating the instant playback of a selected title from a box associated with a user. In one embodiment, the process  686  is employed in a media on demand system. At  688 , the process  686  is awaiting a request from an ordering box associated with a user. Typically, a user selects a title and then places an order. As will be further described below, the ordering box generates a request to be transported to the server. The process  686  is activated when such request including the order is received from the ordering box. In general, the request includes an identifier and an IP address of the ordering box, the user account information (e.g., user name), and the order information. Before anything happens in the ordering box, the process  686  proceeds with authentication of the user. If the user is not registered, the process  686  goes to  691  wherein a response including an error message is generated and returned to the ordering box. Depending on implementation, the error message may activate a local module in the ordering box to display an error message or ask the user to register with the system. 
     After the user is authenticated, the process  686  goes to  692  to determine if payment for the order is settled. In one embodiment, in a registration process, a user may provide credit card information for charges on any order the user places with the system. In another embodiment, the user may receive a monthly statement for collective settlement of charges. If payment is not settled (e.g., the user has a large outstanding balance in his/her account), the process  686  goes to  693  where a response including an error message is generated and returned to the ordering box. The error message may be displayed locally to the user for payment. 
     After payment is settled, the process  686  goes to  694  to determine a number of boxes that are designated to supply the segments to the ordering box. The exact number of boxes depends on the number of segments the ordering box needs to continue the playback of the selected title. At  696 , a response is generated in accordance with the received request. In general, the response includes source information, authentication information and security information. The source information instructs where and how the ordering box can get the needed segment(s) to continue the playback of the selected title. The authentication information allows the ordering box to conduct respective secured communications with boxes designated to supply the needed segment(s). The security information facilitates decryption of any data for the playback of the ordered title. In determining one or more boxes to supply the needed segments among others, one or more several factors may be considered depending on implementation. These factors include, but may not be limited to, respective available bandwidths, geographic locations, histories of availability of these supplying boxes, and the Internet service provider of each box. In addition, whether the ordered title is popular or not, a supplying box is new or not, and a supplying box is busy or not may be considered as well. In any case, the response is transported back to the ordering box or causes the ordering box to start the playback while receiving the needed segments. The process  686  then returns to  688  to await another request. 
     The process  686  shows that, in one embodiment, the server handles only the ordering process and thus can easily manage a large number of requests for different titles at substantially the same time. One of the possible features, advantages and benefits of some embodiments of the present invention is to shift the data-feeding burden to the users to use the collective unused bandwidth and computing power. 
     Referring now to  FIG. 7A , there shows one exemplary implementation of a box  700  that may correspond to any one of the boxes (e.g.,  207 - 1 ,  207 - 2  and  207 - n ) of  FIG. 2A . The box  700  includes a local module  702 , an interface  704 , and a storage space  706 . The local module  702  is loaded in a memory  708  and executed by a processor  710  to perform its operations. In operation, the box  700  may be provided to a subscriber or user by a service provider or an enterprise offering media services to users. Through the network  712 , the box  700  can receive the media services provided by a server (e.g., the server  600  of  FIG. 6A ). As stated above, examples of the box  700  may include, but not be limited to, a desktop computer, a laptop or notebook computer, a set-top box, a portable device such as a telephone, tablet PC or PDA, etc. The network  712  is preferably a broadband local loop that uses one or more of xDSL, ATM, SONET, fiber optic lines, a private/public telephone network, a wireless connection, or CAT-5. The box  700  is coupled to the network  712  by way of a circuit-switched or packet-switched connection. 
     As shown in  FIG. 7A , there are a plurality of modules that are configured to work cooperatively with each other. It is understood to those skilled in the art that not every module listed in the local module  702  of  FIG. 7A  must be employed. Depending on actual implementation or needs, the modules may be selectively deployed. 
     Status reporting module  714  is provided to monitor various statuses affecting the box  700 . In one situation, whenever the IP address of the box  700  is changed, the status reporting module  714  reports the new IP address immediately to the server. In another situation, the status reporting module  714  is configured to detect how long the box has been out of the network so that a library in the box can be appropriately updated in a timely fashion. In still another situation, the status reporting module  714  detects the available uploading bandwidth. If the uploading bandwidth is below a certain number, the status reporting module  714  will inform the server in a timely manner so that the box is not to be designated to supply a segment to other boxes. In yet another situation, the status reporting module  714  detects if a segment being fetched from a supplying box is no longer at a desired speed, the status reporting module  714  may cause a communication session to be terminated with the supplying box, and activate a communication session with another supplying box. Other functions performed by the status reporting module  714  may be appreciated in the detailed description herein. 
     Library management module  716  is provided to manage headers and segments for the many titles in the storage space  706 . Through the library management module  716 , the server knows what objects the box has. The library management module  716  also dictates what distributed objects (i.e., missing segments) are to be fetched in reference to an ordered title. As the box fetches or receives headers and segments of new and changing titles, the library management module  716  manages them. It will be appreciated that the library management module  716  may communicate with the server to keep the server up to date on available segments to supply to ordering boxes. Such communications may occur after each event (such as receiving a new segment), at predetermined intervals, and/or the like. 
     Metadata module  718  is provided to facilitate various interactions between the box  700  and a user thereof. The metadata module  718  may be implemented to provide various graphic interfaces to allow the user to browse metadata about the library in the box  700 . The metadata may include, but not be limited to, associated information about actors, directors, reviews, blurbs, ratings, etc. about the titles in the library. In one embodiment, the metadata module  718  accepts entries from the users and display desired information in accordance with the entries. In an exemplary application, a user enters one or more characters. The metadata module  718  goes through the metadata and provides a list of titles in accordance with the entered characters. As more characters are entered, the list is progressively narrowed so that a selection of a title may be made easier. In another exemplary application, the metadata module  718  allows a user to specify a type of a title (e.g., action or romance), a list of titles pertaining to the type is displayed so that a selection of a title may be made. 
     The security module  720  is provided to facilitate secured communications with the server as well as other boxes. In one embodiment, as soon as one of the designated boxes accepts a request from the ordering box to supply a segment, a secured session between the ordering box and the supplying box is established. Consequently, all data transmitted therebetween is secured. The security module  720  is also provided to handle DRM and security of any data for the playback of the ordered title. 
     Learning engine  722  is provided to best serve users from the viewing behavior of a user and/or network behavior of the box associated with the user. From what a user has browsed, selected or ordered, a list of recommended titles may be automatically generated for the user. Also from the viewing behavior, the learning engine  722  can configure the box to decide which segment(s) to cache locally. In a situation in which a box is offline for a period of time, when the box is back online, the learning engine  722  can configure the box to update the library by prioritizing the titles to be fetched. By acquiring the network behavior of the box, the learning engine  722  knows what bandwidth may be available at different times in a day, which may facilitate the designation of the box to supply segments to other boxes or seeding of the box with releases from the server. 
     Registration module  724  allows new users to register with the system. Typically, after a user is successfully registered, the registration module  724  is configured to forward the registration information to the server for centralized management. In operation, the registration module  724  acts as a frontline to guard the system, requiring, for example, a username and password. A user must be authenticated by the registration module  724  before an order can be accepted. 
     Referring now to  FIG. 7B  and  FIG. 7C , both figures collectively show a flowchart or process  730  of starting instant playback of a selection (i.e., a title). The process  730  may be implemented in software, hardware or a combination of both as a method, a process, and/or a system. Preferably, the process  730  is executed in a computing device that may correspond to a box as used herein. Working in conjunction with the process  686  of  FIG. 6G , the process  730  enables instant playback of a file pertaining to a selected title from a box, wherein the file is not completely available at the time of the playback. 
     At  732 , the process  730  awaits a selection from a user. In one case, a user views a display with a plurality of titles from which the user may activate a key (e.g., on a remote control or keyboard) to choose one of the titles. The process  730  is activated when a selection is made by the user. The process  730  goes to  734  to determine whether the user and/or box is properly authenticated. In one embodiment, a registered user is required to input a username and a password for authentication. In another embodiment, a registered user is required to enter a code for authentication. There may be other ways to authenticate a user. In any case, the process  730  needs to ensure that a user and a box is legitimate. If not, the user is sent an error message at  736  that may recommend that the user register with the system. 
     After a registered user has been authenticated at  734 , the box sends a request at  738  in accordance with the selection. The request includes information about the order and the user. The request is transported to the server by a service provider. Upon receiving the request, the server proceeds with process  686  of  FIG. 6G . Meanwhile, the box awaits a response from the server at  740 . The request may be re-sent if a response is not received within a predefined time (e.g., 5 seconds). However, if the response is not received beyond a certain time (e.g., the network is down), an error message will be displayed at  739 . 
     At  742 , the response is received from the server. For proper reason, the response may restrict the user from using the system. If the user is restricted, the process  730  goes to  743  display an error message to the user. Upon authorization, the process  730  goes to  744  where a header of the file pertaining to the selected title is played and may be displayed via a display utility. 
     At  746 , in accordance with the response from the server, the box makes respective requests to other boxes for missing segments. As described above, the response includes source information indicating where the box can fetch the missing segments. For example, if there are four segments for a file and the box stores two of the segments locally, then two segments must be fetched from other boxes. At  748 , the box awaits a response from the boxes being requested to supply the missing segments. If one of the boxes is unable to respond to the request, a backup box may be called upon to supply the segment. If the backup box is also unable to respond to the request, the box will send a request to the server for additional backup boxes. In any case, after the designated boxes respond to the requests from the ordering box, the ordering box at  750  starts to fetch the missing segments from the designated and responded boxes. 
     As described above, the missing segments are expected to arrive at a predetermined speed. If, for some reason, a portion of the network is congested or the box itself is malfunctioning, causing a significant slowdown of the segment being fetched, the process  730  goes to  754  where a backup box is called in to continue supplying the segment being interrupted. The details of  752  and  754  are further described in  FIG. 7E . 
     If all segments are streaming at predetermined minimum speeds, then, at  756 , portions of the segments locally stored and the portions of the segments being streamed in are multiplexed into a buffer as shown in  FIG. 7D . A buffer  770 , preferably part of the memory  708  of  FIG. 7A , is loaded with data of the header  772 . As shown in  FIG. 7D , a portion  774  of the header  772  has been played out of the buffer  770 . The remaining portion  776  of the header  772  is yet to be played. At the same time, the streaming of segments  778  and  780  is being fed into the buffer  770 . Segments  778 - 781  (including the segments locally stored and the segments being streamed in) are multiplexed into the buffer  770 . More specifically, a block of data from segment  1 , a block of data from segment  2 , a block of data from segment  3  and a block of data from segment  4  are multiplexed and successively fed into the buffer  770 . As a result, the original order of the data is restored and the remaining portion of the file pertaining to the title is assembled. 
     Referring back to  FIG. 7C , the process  730  goes to  758  to continue playback of the assembled data in the buffer until the entire file for the ordered title is played. The process  730  then goes back to  732  to await another order from the user. 
     Referring back to  FIG. 7D , there show two pointers  782  and  784 . Each of the pointers  782  and  784  is used to remember where the data block of a segment is being fed or about to be fed to the buffer  770 . In the event, the segment being fetched from a box is interrupted and a backup box is stepped in, the ordering box knows exactly where to start fetching the segment from where it was interrupted in accordance with the pointer. Likewise, similar pointers (not shown) may be provided to remember where the data block of the locally cached segment is being fed or about to be fed to the buffer  770 . In the event, the ordering box needs to be reset or is suddenly powered off and back on, these pointers can facilitate the continuation of the playback of the ordered title. 
     It has been described that a box may execute a number of tasks such as facilitating a search of a desired title among all titles in a library, fulfilling an order from a user, supplying one or more segments to other boxes, updating the library in responding to a release, and reporting its status or network status to a server. Although all tasks are equally important, some may be prioritized ahead of others. 
     Referring now to  FIG. 7E , there shows a flowchart or process  784  of prioritizing tasks in a box according to one embodiment. It should be noted that the process  784  may make the system more efficient. Upon install, a box is not requested to supply or upload a segment to another box. The box is configured to report at  786  its status to a server (e.g.,  202  of  FIG. 2A ) periodically or at a predefined time, synchronize with a counterpart box for updating a release to its library or perform other operations that may affect the overall performance of the box. When reporting to the server, the box sends out a status that may indicate its working condition. In one embodiment, the box is coupled to a public network and assigned a dynamic IP address. To ensure that the box is in communication with the server and other boxes, the box is configured to report any IP address change to the server. 
     The box either enters a waiting mode or performs other operations at  786 . As the box may be a candidate to supply one or more segments to an ordering box, at  788 , the process  784  checks whether the box has been requested to supply any segment to another box. If there is no such request received, the box returns to  786  to keeping on doing whatever it was doing. However, upon receiving a request from an ordering box at  788 , the process  784  goes to  790  to locate a requested segment among many segments residing in the box. At  792 , the box checks whether the uploading bandwidth is sufficient. It is assumed that the uploading bandwidth available at the time of the request is W and the bandwidth required to upload the segment is R. If W&gt;R, the process  784  goes to  796 , which means any operations, if there are any, that are using the uploading bandwidth are not concerned. If W&lt;R, the process  784  goes to  794  where any other operations, if there are any, that are using the uploading bandwidth are stopped immediately. Example operations that may take uploading bandwidth includes uploading a release package requested by a counterpart box or seeding a new box. 
     After such operations are suspended, the process  784  goes to  796  to upload the requested segment to the ordering box. At  798 , it is determined whether the uploading of the requested segment is finished. If not, the uploading is continued. When the requested segment is finished uploading, the process  784  goes to  786  to restore or continue what the box was doing or is supposed to be doing. 
     It should be noted that the process  784  is described for uploading one segment. Those skilled in the art will understand that the process  784  is applicable to uploading more than one segment if the uploading bandwidth permits. It is described above that more than one segment for a top band typically resides in a box. When the uploading bandwidth of a box to the ordering box is sufficient to upload more than one segment, in one embodiment, such box may be designated to upload more than one segment so that the playback of a selected title depends less on other boxes. 
       FIG. 8  shows an architecture  800  in which many aspects of the present invention are equally applied thereto. The architecture  800  may include all the functionality of the architecture of  FIG. 2A . As an enhancement to the architecture of  FIG. 2A , the architecture  800  includes a server database storing all distributed objects. By storing the distributed objects, the server may support ordering boxes when backup boxes fail, as an initial backup box, when bandwidth is available, etc. 
     It should be appreciated that the server, in response to a request for a title by an ordering box, need not respond directly to the ordering box. The server  202  may respond by providing instructions to distributed boxes to provide distributed objects to the ordering box. The server  202  may respond by requesting distributed boxes to volunteer their services. Many other possible responses by the server are also possible. It should be further appreciated that requests by ordering boxes need not go to the server. For example, boxes may be given network configuration maps, so that the boxes can make requests directly to other boxes, thereby avoiding using server bandwidth for playback requests. 
     One skilled in the art will recognize that elements of the system may be implemented in software, but can be implemented in hardware or a combination of hardware and software. The invention can also be embodied as computer-readable code on a computer-readable medium. The computer-readable medium can be any data-storage device that can store data which can be thereafter be read by a computer system. Examples of the computer-readable medium may include, but not be limited to, read-only memory, random-access memory, CD-ROMs, DVDs, magnetic tape, hard disks, optical data-storage devices, or carrier wave. The computer-readable media can also be distributed over network-coupled computer systems so that the computer-readable code is stored and executed in a distributed fashion. 
     Possible advantages of the invention are numerous. Different embodiments or implementations may yield one or more of the following benefits, features, and advantages. One of them is the instantaneous feature in a media-on-demand system. With a small portion of a file pertaining to a title locally cached, the remaining portion of the file is distributed in segments across one or more boxes. After a title is ordered, provided that a user is authenticated and a payment is properly settled, the locally cached portion is immediately played; during the playback of this locally cached portion, the remaining portion is fetched from the boxes as streams to continue the playback of the title. Another one of them is the way a file is fragmented. Given a file pertaining to a title, the file is fragmented into a header and several segments. The header is a continuous portion of the file while each of the segments is a decimated portion for the remaining portion for the file. As the segments are being fetched, the segments are multiplexed to restore the order of the original data for playback. Still another possible benefit, feature, and advantage is the underlying mechanism of updating a library in a box synchronously or asynchronously without preventing the box from servicing others. When a release becomes available, a release package to be locally cached is propagated asynchronously to the box from other boxes, instead of being transmitted from a central server. Other benefits, features, and advantages are also possible. 
     The foregoing description of embodiments is illustrative of various aspects/embodiments of the present invention. Various modifications to the present invention can be made to the preferred embodiments by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims. For example, in one embodiment, the size of a header for a file may be reduced to zero, in other words, a file is fragmented into a plurality of segments that can be distributed into boxes. Also, when an order of a title is placed, the server may identify the sources that will supply data for the order, and then contact these suppliers itself to initiate data transfers, instead of requiring the ordering box to initiate communication with the sources. In fact, an ordering box could even dynamically obtain the source information from boxes that cache respective segments for the title instead of requiring the server to identify the supplying boxes. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description of embodiments.