Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS20020052932 A1
Publication typeApplication
Application numberUS 09/993,639
Publication dateMay 2, 2002
Filing dateNov 27, 2001
Priority dateJun 11, 1998
Also published asCA2334737A1, EP1110149A1, EP1110149A4, US6338086, WO1999064959A1
Publication number09993639, 993639, US 2002/0052932 A1, US 2002/052932 A1, US 20020052932 A1, US 20020052932A1, US 2002052932 A1, US 2002052932A1, US-A1-20020052932, US-A1-2002052932, US2002/0052932A1, US2002/052932A1, US20020052932 A1, US20020052932A1, US2002052932 A1, US2002052932A1
InventorsPavel Curtis, Micheal Dixon, David Nichols
Original AssigneePlaceware, Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Collaborative object architecture
US 20020052932 A1
Abstract
A collaborative object architecture with one or more of the following technologies: 1) lightweight asynchronous messaging; 2) collaborative objects; 3) optimistic concurrency control; and 4) transparent object serialization. Lightweight asynchronous messaging allows highly responsive interactivity and natural interactions with minimal network loads. Collaborative objects allow ubiquitous sharing and provides each user with the same copy of the shared object. Optimistic concurrency control allows full-duplex group editing and natural interactions. Transparent object serialization provides real world persistence and support for asynchronous changes. Thus, combination of these technologies provides a collaborative object architecture with several advantages over the prior art.
Images(10)
Previous page
Next page
Claims(19)
What is claimed is:
1. A collaborative-object architecture comprising:
a first computer system running a pod having a first set of constituent parts; and
a second computer system coupled to the first computer system, the second computer system running an applet having a second set of constituent parts, the pod and the applet together comprising a collaborative object, wherein the first set of constituent parts correspond to the second set of constituent parts such that changes to one of the second set of constituent parts cause corresponding changes to a corresponding constituent part in the first set of constituent parts;
wherein the applet receives input and generates a message to the pod in response to the input, and further wherein the applet applies the input without waiting for a response from the pod.
2. The architecture of claim 1, wherein the applet generates a message packet to the pod comprising multiple messages, and further wherein the messages are optimized to reduce non-essential data included in each message.
3. The architecture of claim 1, wherein data controlled by the pod is serialized and stored on a data storage device if a message packet is not received by the pod for a preselected period of time.
4. The architecture of claim 1, wherein the pod receives message packets from the applet and communicates the packets to additional applets.
5. The architecture of claim 1, wherein the pod receives message packets from multiple applets, determines an order in which to process the received message packets and communicates a set of data resulting from the processing to the multiple applets such that the multiple applets receive the set of data from messages originating from the pod.
6. A method for a collaborative-object architecture comprising:
running a pod having a first set of constituent parts on a server computer system coupled to a first client computer system running a first applet having a second set of constituent parts and to a second client computer system running a second applet having a third set of constituent parts;
receiving a message from one of the second set of constituent parts indicating a change to data controlled by the constituent part;
processing the message by changing a corresponding constituent part in the first set of constituent parts based on the message, wherein the first applet continues normal execution prior to the processing of the message; and
sending an update to the second applet indicating the change corresponding to the message.
7. The method of claim 6, wherein the step of receiving a message comprises receiving a message packet having multiple messages indicating changes to data controlled by the constituent part.
8. The method of claim 6, wherein the update comprises multiple messages, and further wherein the messages are optimized to reduce non-essential data included in each message.
9. The method of claim 6, wherein the step of receiving a message further comprises:
receiving a message from multiple applets;
determining an order in which to process the multiple messages; and
transforming incoming messages, if necessary, based on a state of the sending applet.
10. A computer readable medium having stored thereon sequences of instructions which when executed cause a processor to:
run a pod having a first set of constituent parts on a server computer system, wherein the server computer system is coupled to a first client computer system running a first applet having a second set of constituent parts and to a second client computer system running a second applet having a third set of constituent parts;
receive a message from one of the second set of constituent parts indicating a change to data controlled by the constituent part;
process the message by changing a corresponding constituent part in the first set of constituent parts based on the message, wherein the first applet continues normal execution prior to the processing of the message; and
send an update to the second applet indicating the change corresponding to the message.
11. The computer readable medium of claim 10, wherein the sequences of instructions further comprise sequences of instruction that, when executed, cause the processor to receive a message packet having multiple messages indicating changes to data controlled by the constituent part.
12. The computer readable medium of claim 10, wherein the update comprises multiple messages, and further wherein the messages are optimized to reduce non-essential data included in each message.
13. The computer readable medium of claim 10, wherein the sequences of instruction that cause the processor to receive a message further comprise sequences of instructions that cause the processor to:
receive a message from multiple applets;
determine an order in which to process the multiple messages; and
transform incoming messages, if necessary, based on a state of the sending applet.
14. A method for a collaborative-object architecture comprising:
running an applet having a first set of constituent parts;
receiving an input that indicates a change to data controlled by one of the first set of constituent parts;
generating a message indicating the change to the data;
sending the message to a pod having a constituent part corresponding to the constituent part receiving the change; and
continuing running the applet without waiting for a response from the pod.
15. The method of claim 14, wherein generating a message comprises generating multiple messages, and further wherein the messages are optimized to reduce non-essential data included in each message.
16. The method of claim 14, further comprising:
receiving an update from the pod indicating changes to the data;
transforming the update, if necessary, based on the state of the pod when the update is generated; and
modifying the data based on the update.
17. A computer readable medium having stored thereon sequences of instructions that, when executed, cause a processor to:
run an applet having a first set of constituent parts;
receive an input that indicates a change to data controlled by one of the first set of constituent parts;
generate a message indicating the change to the data;
send the message to a pod having a constituent part corresponding to the constituent part receiving the change; and
continue running the applet without waiting for a response from the pod.
18. The computer readable medium of claim 17, wherein the sequences of instructions that cause the processor to generate a message further comprise sequences of instructions that cause the processor to generate multiple messages, wherein the messages are optimized to reduce non-essential data included in each message.
19. The computer readable medium of claim 17, further comprising sequences of instruction that, when executed, cause the processor to:
receive an update from the pod indicating changes to the data;
transform the update, if necessary, based on the state of the pod when the update is generated; and
modify the data based on the update.
Description
    FIELD OF THE INVENTION
  • [0001]
    The present invention relates to multi-user computer applications. More specifically, the present invention relates to a collaborative object architecture for use with networked computers.
  • BACKGROUND OF THE INVENTION
  • [0002]
    Advances in computer technology and the advent of the Internet have enabled geographically distributed computer users to execute computer programs from points around the world. Examples of distributed programs include computer chat rooms, conferencing programs and gaming programs, each of which allow multiple computer users to interactively exchange information in real time. For instance, a computer chat room can allow a number of distributed users to view conversational text as it is typed by any one of the individual users, a conferencing application may allow geographically distributed users to collectively draft and edit a single text document, and gaming programs can allow multiple users to compete or collaborate in a virtual gaming environment.
  • [0003]
    In order to perform distributed programming, it is necessary for two individual processes to maintain a bi-directional communication stream. The term “process” refers to an active execution of a computation, and is also commonly referred to as a task, job, or thread. Distributed programming is frequently based on the client-server paradigm, wherein a process executing on a client system communicates with a process executing on a server system.
  • [0004]
    In the client-server paradigm, a client process makes requests for access to, and information from, a server process. A client process and server process can be executing on the same computer system or they can be executing on separate networked systems. In an architecture where a server is accessible by a network, such as the Internet, a large number of client systems from around the world can make requests on a server system.
  • [0005]
    Distributed programs, however, typically are only distributed to the extent that multiple client systems have access to a program running on a server system that operates with request and wait remote procedure calls (RPCs). In these architectures, the client systems request a service from the server system and wait for a response before proceeding. Such architectures require substantial network resources to keep the client systems updated with changes to the program. As the number of users increases network and other computing resources required to provide satisfactory performance also increases. For these reasons, prior art distributed programs typically do not provide a scalable, near real time collaborative environment.
  • [0006]
    What is needed is an improved architecture that provides objects distributed among multiple computer systems that act as a single object.
  • SUMMARY OF THE INVENTION
  • [0007]
    A collaborative object architecture is described. A pod application runs on a server computer system. Applets run on one or more client computer systems coupled to the server computer system via a network. Each pod and a corresponding applet on each client computer system comprises a collaborative object. In one embodiment, pods have multiple constituent parts having corresponding constituent parts in each corresponding applet. Changes generated by a constituent part in an applet are processed locally and communicated to the pod. The applet continues normal operation without waiting for a response from the pod. When the pod receives the changes, the corresponding constituent part processes the changes and communicates the changes to the applets that have not processed the changes. In one embodiment, multiple changes are communicated in a single message packet.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0008]
    The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements.
  • [0009]
    [0009]FIG. 1 is one embodiment of a computer system.
  • [0010]
    [0010]FIG. 2 is one embodiment of a collaborative object architecture.
  • [0011]
    [0011]FIG. 3 is one embodiment of a conceptual diagram of lightweight asynchronous messaging.
  • [0012]
    [0012]FIG. 4 is one embodiment of a distributed database having collaborative objects.
  • [0013]
    [0013]FIG. 5 is one embodiment of two messages of a single string object that cross in a network.
  • [0014]
    [0014]FIG. 6 is one embodiment of a state space for an applet and a pod while processing messages.
  • [0015]
    [0015]FIG. 7 is one embodiment of a state space in which an applet and a pod diverge by more than one step.
  • [0016]
    [0016]FIG. 8 is one embodiment of a flow diagram for sending a message.
  • [0017]
    [0017]FIG. 9 is one embodiment of a flow diagram for receiving a message.
  • DETAILED DESCRIPTION
  • [0018]
    A collaborative object architecture is described. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention can be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the present invention.
  • [0019]
    Briefly, the present invention provides a collaborative object architecture with one or more of the following: 1) lightweight asynchronous messaging; 2) collaborative objects; 3) optimistic concurrency control; and 4) transparent object serialization. Lightweight asynchronous messaging allows responsive interactivity and natural interactions with minimal network loads. Collaborative objects allow ubiquitous sharing and provides each user with the same copy of a shared object. Optimistic concurrency control allows full-duplex group editing and natural interactions. Transparent object serialization provides real world persistence and support for asynchronous changes. Thus, combination of these features provides a persistent collaborative-object messaging architecture with several advantages over the prior art.
  • [0020]
    Overview of a Collaborative Object Architecture
  • [0021]
    [0021]FIG. 1 is one embodiment of a computer system. Computer system 100 includes bus 101 or other communication device for communicating information, and processor 102 coupled with bus 101 for processing information. Computer system 100 may also include multiple processors (not shown in FIG. 1). Computer system 100 further includes random access memory (RAM) or other dynamic storage device 104 (referred to as main memory), coupled to bus 101 for storing information and instructions to be executed by processor 102. Main memory 104 also can be used for storing temporary variables or other intermediate information during execution of instructions by processor 102. Computer system 100 also includes read only memory (ROM) and/or other static storage device 106 coupled to bus 101 for storing static information and instructions for processor 102. Data storage device 107 is coupled to bus 101 for storing information and instructions.
  • [0022]
    Data storage device 107 such as a magnetic disk or optical disc and its corresponding drive can be coupled to computer system 100. Computer system 100 can also be coupled via bus 101 to display device 121, such as a cathode ray tube (CRT) or liquid crystal display (LCD), for displaying information to a computer user. Alphanumeric input device 122, including alphanumeric and other keys, is typically coupled to bus 101 for communicating information and command selections to processor 102. Another type of user input device is cursor control 123, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor 102 and for controlling cursor movement on display 121.
  • [0023]
    [0023]FIG. 2 is one embodiment of a collaborative object architecture. In one embodiment, each data set (or object) within the architecture has two distinct parts: one part that runs on a single server computer system and one or more copies of the second part that run on separate client computer systems, each of which connect to the server computer system via a network. The phrase “data set” refers to a broad category of objects including, but not limited to, applications, files, etc.
  • [0024]
    For purposes of explanation herein, individual client parts of each application are called “applets.” In one embodiment, applets run in a Web browser, such as Internet Explorer® available from Microsoft Corporation of Redmond, Washington or Navigator® available from Netscape Communications, Inc. of Mountain View, Calif. Alternatively, the applet can run in a different web browser or as a standalone application. In one embodiment, applets are built of classes defined by the Java™ Programming Language available from Sun Microsystems of Mountain View, Calif.; however, any programming language can be used.
  • [0025]
    In alternative embodiments, applets are standalone applications (client applications) rather than applets running in a Web browser. In such embodiments, the client applications are installed in a client computer system prior to communication with a server.
  • [0026]
    When a server application is running on a server computer system, the server accepts connections from clients and activates or deactivates server-side applications in response to the connections. For explanation purposes herein, the server half of an application is referred to as a “pod.” The server also maintains the persistent state of the pods.
  • [0027]
    A server provides an environment in which pods can run and receive connections from corresponding applets. In one embodiment, the server responds to TCP or HTTP connections made by client-side messaging substrate(s) and generates a sub-connection to an appropriate pod. It is important to note that any type of communication protocol that provides reliable, ordered communications can be used to implement the present invention.
  • [0028]
    Each collaborative object includes multiple constituent parts including a pod and one or more applets distributed across multiple computer systems. Applets and pods can be further subdivided into constituent sub-parts, which interact to provide collaborative sub-objects. Sub-parts can be further subdivided into multiple levels of sub-parts each of which interact with corresponding sub-parts to provide multiple levels of collaborative sub-objects. The relationship of constituent parts across multiple computer systems and the hierarchical relationship of sub-parts is described in greater detail below.
  • [0029]
    Network 200 provides an interconnection between multiple computer systems that operate as client computer systems and/or server computer systems. Network 200 can be any type of computer network. In one embodiment, network 200 is the Internet. Alternatively, network 200 can be local-area network (LAN), a wide-area network (WAN), etc.
  • [0030]
    [0030]FIG. 2 describes a single server communicating with to a single web browser via network 200 for simplicity. Any number of web browsers and any number of servers can be interconnected via network 200 and additional networks (not shown in FIG. 2); however, collaborative objects operate between a single server and multiple clients. In one embodiment, the network connection provides an applet with a bi-directional communication channel with the corresponding pod. In one embodiment, the communication takes the form of asynchronous remote procedure calls (RPCs) made by each side to the other.
  • [0031]
    Web browser 220 runs on a client computer system (not shown in FIG. 2) that provides computing resources for web browser 220. Similarly, server application 240 runs on a server computer system (not shown in FIG. 2) that provides computing resources for server application 240. The particular environment in which applets and pods run may be varied and is not central to the present invention.
  • [0032]
    Web browser 220 runs one or more applets, such as applet 222 and applet 224. In one embodiment, each applet can be further subdivided into multiple constituent parts, such as constituent parts 212, 214, 216, 232 and 234. Constituent parts can be, for example, a shared string, a shared integer, etc.
  • [0033]
    Server 240 runs one or more pods, such as pods 250 and 260. In one embodiment, each pod can be further subdivided into multiple constituent parts that correspond to respective constituent parts of applets running in web browser 220 or other web browsers (not shown in FIG. 2). For example, pod 250 corresponds to applet 210 and the three constituent parts of pod 250 (e.g., 252, 254 and 256) correspond to the three constituent parts (e.g., 212, 214 and 216) of applet 210. Similarly, the two constituent parts of pod 260 (e.g., 262 and 264) correspond to the two constituent parts of applet 230 (e.g., 232 and 234).
  • [0034]
    Communication between applets and corresponding pods occur over network 200. The network connection provides applets with a bidirectional communication channel with the corresponding pod. In one embodiment, the communication takes the form of asynchronous remote procedure calls (RPCs) made by each side to the other. Asynchronous communication is described in greater detail below.
  • [0035]
    Lightweight Asynchronous Messaging
  • [0036]
    In one embodiment, pods and applets communicate via a messaging substrate.
  • [0037]
    The messaging substrate is an optimized facility designed specifically to support interactive distributed applications running on any network. The messaging substrate is designed for performance using high-latency networks by using small messages to reduce bandwidth requirements.
  • [0038]
    Network interactions are generally subject to two sources of response latency.
  • [0039]
    The first source of response latency is caused by sequential processing of events by a pod. Sequential processing refers to ordering of events that occur simultaneously or are received simultaneously by the pod. The second source of response latency is high-latency communications paths. For example, low-bandwidth connections, busy networks, and high-latency links introduce delays to responses from other devices.
  • [0040]
    In one embodiment, asynchronous lightweight messaging allows applets to continue operation without waiting for a response from the corresponding pod. Thus, unlike rigid “call and return” messaging, applets are not left idle waiting for pod response. Similarly, pods continue local operations without waiting for the applet to respond. Thus, both the pod and the applet can continue operations without waiting for a response from the other device, thereby improving interactivity of distributed applications.
  • [0041]
    In order to properly implement asynchronous lightweight messaging, the underlying transport protocol must be reliable and provide ordered delivery. In other words, messages sent by an applet are received by a corresponding pod in the same order in which the messages were sent. In one embodiment, TCP is used for messaging purposes; however, any protocol that provides reliable, ordered delivery of messages can be used.
  • [0042]
    [0042]FIG. 3 is one embodiment of a conceptual diagram of lightweight asynchronous messaging. Network 300 provides interconnection between server 320, web browser 340 and web browser 360. Pods 322, 324 and 326 run in server 320. Applets 342 and 344 run in web browser 340. Similarly, applets 362 and 364 run in web browser 360.
  • [0043]
    Message bursts generated by the web browsers and the server can include multiple messages. For example, message burst 350 includes two messages generated by an applet running in web browser 360. The term “message bursts” refers to any grouping of messages sent across a network, regardless of network protocol and packet format. Message burst 330 includes three messages generated by an applet running in web browser 340. Pods communicate messages in a similar manner. For example, message burst 310 includes four messages from a pod running in server 320.
  • [0044]
    In one embodiment, compact representations are used to reduce the amount of data included in each message. For example, if an integer is less than 256, the number is sent as one byte of data. Larger integers are sent as larger blocks of data. Similar compact representations are used for other data. In this manner messages are optimized to reduce the non-essential data included in each message. Lightweight messaging allows small change information to be sent frequently. This makes the collaborative object appear more “live” because the user receives better feedback. Lightweight messaging is also beneficial for use with high-latency networks such as the Internet for the same reason.
  • [0045]
    As described above, multiple messages can be bundled into a single message burst. For example, multiple messages can be included in a single TCP packet or HTTP request. The asynchronous nature of messaging provided by the present invention allows message bundling because a sending object is not required to wait for a response from the receiving object. In a call and return architecture only a single message can be sent because the sending object cannot proceed without a response from the receiving object.
  • [0046]
    In one embodiment, a single TCP connection is shared between all applets running on a single browser and a corresponding server application running corresponding pods. The constituent sub-parts of an applet communicate with the corresponding constituent sub-parts of a pod over the shared connection.
  • [0047]
    Collaborative Objects
  • [0048]
    Collaborative objects refers to many constituent parts on many hosts that act as a single object. As discussed above, each object has a server side (pod) and one or more client sides (applets). Each pod and/or applet can be further sub-divided into constituent parts that communicate with corresponding constituent parts. In one embodiment, constituent parts are chosen from a library of constituent parts; however, custom constituent parts can be designed.
  • [0049]
    The library of constituent parts can provide lower-level functionality, such as constituent parts that manipulate strings, numerical values, etc. Higher-level collaborative objects can be built from the lower-level collaborative objects included in the library. For example, a database query higher-level collaborative object can include multiple string objects and multiple integer objects. The database query object can then be shared by multiple applets and a corresponding pod.
  • [0050]
    Collaborative objects also provide an applet with more local intelligence than prior art shared objects operating with a call and return protocol. An applet can provide local processing of shared objects without the need of communicating with the pod. For example, an applet can search a local copy of a collaborative string object to determine whether a particular sub-string exists without communicating a search request to the pod. Thus, applet operations do not necessarily correspond with remote procedure calls.
  • [0051]
    [0051]FIG. 4 is one embodiment of a distributed database having collaborative objects. In the example of FIG. 4, the collaborative object is a database; however, collaborative objects can operate on any set of data, whether executable or not. Constituent parts of the collaborative object can be used, for example, to author queries, modify data, etc.
  • [0052]
    Server application 410 runs a pod that consists of pod core 412, collaborative integer constituent part 414 and collaborative string constituent part 416. Pod core 412 has access to data 420 that is not a part of server application 410. As described in greater detail below, applets do not directly intercommunicate. Applets send messages to a corresponding pod and the pod manages coordination of collaborative objects.
  • [0053]
    Web browser 450 runs applet 470 that includes applet core 452, collaborative integer constituent part 454 and collaborative string constituent part 456. Similarly, Web browser 440 runs applet 460 that includes applet core 442, collaborative integer constituent part 444 and collaborative string constituent part 446. In one embodiment, the collaborative string constituent parts and the collaborative integer constituent parts are multiple instances of objects defined by the object library.
  • [0054]
    In one embodiment, pod core 412, applet core 442 and applet core 452 provide code sequences to manage communications between the pod/applet over shared TCP connections. For purposes of explanation with respect to FIG. 4, the core components include the messaging substrate described above. In one embodiment, the constituent parts that are included in pods and applets communicate with corresponding constituent parts in the manner described above in more general terms with respect to applets and pods.
  • [0055]
    Collaborative string constituent parts 416, 446 and 456 are corresponding constituent parts that provide a collaborative string object used to define a query into the database to retrieve data from data 420. When a user of web browser 450 writes a query using a keyboard or other input device (not shown in FIG. 4), the query is input to a user interface (not shown in FIG. 4) of web browser 450. The user interface communicates the query to collaborative string constituent part 456 that modifies a local copy of the string. Collaborative string constituent part 456 then communicates the query to collaborative string constituent part 416. In one embodiment, the query is communicated as part of a message burst between applet 470 and pod 480.
  • [0056]
    Collaborative string constituent part 416 updates the server-side local version of the string in response to the message received from applet 470. Coordination of messages between multiple applets and a corresponding pod is described in greater detail below. Collaborative string constituent part 416 then communicates the query to collaborative string constituent part 446 that is part of applet 460, as well as to any other corresponding applets (not shown in FIG. 4). Collaborative string constituent part 446 changes the local copy of the string and communicates the string to the user interface (not shown in FIG. 4) of Web browser 440.
  • [0057]
    In one embodiment, communications occur directly between the constituent parts of a collaborative object. The corresponding pod and applets do not manage communications or updates to data controlled by the constituent parts. In this manner, constituent parts of applets and pods as well as constituent sub-parts along with corresponding parts or sub-parts operate as collaborative objects or collaborative sub-objects, without management by the higher-level applets and pod. By providing independent objects operating together to form a higher level applet or pod, the present invention allows use of asynchronous communications between parts to provide a more responsive architecture than prior art shared object architectures.
  • [0058]
    The user of web browser 440 can also make modifications to the string to change the database query. Any changes to the string are processed in the same manner as the original query described above. Of course, other constituent parts can be used to provide different data in a similar manner. For example, collaborative integer constituent parts 414, 444 and 454 can be used for communicating other data between within collaborative objects, for example, updating data 420.
  • [0059]
    Constituent parts can be further subdivided into multiple constituent sub-parts or larger collaborative objects can be built from constituent parts (not shown in FIG. 4). For example, collaborative string constituent part 416 and collaborative integer constituent part 414 together can define a database query pod constituent part. The corresponding applet constituent parts define respective database query applet constituent parts. Together the constituent parts provide a database query collaborative object. Constituent sub-parts communicate directly with corresponding constituent sub-parts in the same manner as the constituent parts described above.
  • [0060]
    Because objects and sub-objects communicate using lightweight asynchronous messaging, changes to an object are made without update and coordination with other objects of the same applet. For example, changes to collaborative integer constituent part 444 can be communicated after changes to collaborative string constituent part 446 are communicated, but before the pod has completed processing of the changes to collaborative string constituent part 446. This allows a user to continue to use an applet without having to wait for processing of previous changes to be completed.
  • [0061]
    Transparent Object Serialization
  • [0062]
    As used herein, “serialization” refers to the process of transforming a complex data set (e.g., a database) into a linear data set that can be stored on data storage device (e.g., a hard disk). In one embodiment, object serialization is used to provide persistence for collaborative objects.
  • [0063]
    According to one embodiment of the present invention, unless active, pods reside on a hard disk or other storage device in the server computer system. When a connection is received for an inactive pod stored on a hard disk, the server computer system loads the pod into main memory and restores the state of the pod as of the last time the pod was active. The server then delivers the incoming messages to the active pod.
  • [0064]
    In one embodiment, when the pod's messages have been processed and the pod is no longer active, the server saves the state of the pod, moves the pod to hard disk or other storage device and clears the pod from main memory. By having the pod in main memory only when connections are open to the pod, a server computer system can support a large number of pods without using correspondingly large amounts of memory. Thus, pods consume resources of the server computer system only when active and being used by clients.
  • [0065]
    Periodic serialization can initiated to maintain persistence for collaborative objects. In one embodiment, servers serialize objects that have been active for a preselected period of time without serialization. Periodic serialization allows the state of the pod to be saved when the pod is active so that the state can be retrieved should an event occur that would cause the pod to lose data, such as the server computer system crashing. In order to coordinate the state of the pod with the stored state, periodic serialization should occur between messages.
  • [0066]
    Optimistic Concurrency Control
  • [0067]
    In general, two types of concurrency control (e.g., pessimistic and optimistic) and two types of collaborative architectures (e.g., centralized and distributed) can be provided, which results in four choices for concurrency control. Pessimistic concurrency control requires communication with other systems (e.g., a server) before changing locally (e.g., the client). Optimistic concurrency control, on the other hand, does not require communications before making a local change. Optimistic algorithms are well-suited for high-latency comminations because the result of a user's action can be displayed before an associated message makes a round-trip between the applet and the server.
  • [0068]
    In distributed architectures, applets communicate with other applets to provide concurrency control. In centralized architectures, applets communicate with pods and the pods provide concurrency control. Because of the many possible messages required, distributed optimistic concurrency control can become complex very rapidly as applets are added to the architecture. The increased complexity increases network resources required to provide concurrency control between applets. One embodiment of optimistic concurrency control is described in detail in a paper entitled “HIGH-LATENCY, LOW-BANDWIDTH WINDOWING IN THE JUPITER COLLABORATION SYSTEM” published in the Proceedings of the Eighth Annual Symposium on User Interface Software and Technology (UIST), Nov. 15-17, 1995. As described in greater detail below, the present invention provides a centralized architecture with optimistic concurrency control.
  • [0069]
    In one embodiment of the present invention, optimistic concurrency control is provided only for individual applet-pod links. In this manner, each applet appears to operate synchronously with respect to the pod. The pod can use a change propagation algorithm to update all applets and thereby provide concurrency control between applets. In one embodiment, if either the applet or the pod initiates a change to data, the change is applied locally and a message describing the change is sent to the other party.
  • [0070]
    As discussed earlier, optimistic concurrency control allows applets to change data without having to wait for pod interaction. If either the applet or the pod initiates a change, the change is immediately applied locally and a message is sent to the corresponding party. When messages cross in the network, each receiver modifies the incoming message so that the message makes sense relative to the receiving object's current state. Modifying conflicting messages is described in greater detail below.
  • [0071]
    Concurrency control is not applied directly between applets, instead concurrency control is applied between a pod and a single applet as messages are received from the individual applets. Changes are then broadcast to the other corresponding applets. In this manner, a two-way optimistic concurrency control algorithm can be applied to an n-way collaborative object architecture, which is much simpler than implementing the n-way optimistic concurrency control.
  • [0072]
    [0072]FIG. 5 is one embodiment of two messages of a single string object that cross in a network. The example of FIG. 5 is an update conflict that results in an incorrect update. Concurrency control of the present invention allows collaborative objects to recognize the conflict and modify messages when necessary to avoid such conflicts.
  • [0073]
    If the messages of FIG. 5 are not transformed on receipt, the final values in applet 550 and pod 510 are different. The original strings, string 552 in applet 550 and string 512 in pod 510 are the same (“ABCDE”). The user of applet 550 deletes “D” and applet 550 generates DEL4 message 554 in response to delete the fourth letter in string 552, which results in string 556 (“ABCE”). DEL4 message 554 is communicated to pod 510 via network 500.
  • [0074]
    Prior to pod 510 processing DEL4 message 554 from applet 550, a user of pod 510 deletes “B” and pod 510 generates DEL2 message 514 in response to delete the second letter in string 512, which results in string 516 (“ACDE”). DEL2 message 514 is then communicated to applet 550 via network 500. Prior to processing the delete messages, string 556 in applet 550 includes “ABCE” and string 516 in pod 510 includes “ACDE”.
  • [0075]
    When pod 510 processes DEL4 message 554, the fourth letter in the string (“E”) is deleted to result in string 520 (“ACD”). Similarly, when applet processes DEL2 message 514, the second letter in the string (“B”) is deleted to result in string 560 including “ACE”. Thus, without concurrency control, the final string in applet 550 and pod 510 do not match.
  • [0076]
    Concurrency control according to the present invention modifies DEL4 message 554 from applet 550 to a DEL3 message to delete “D” from string 516 instead of deleting “E”. As described below, the architecture of the present invention includes concurrency control to handle update conflicts so that pods and corresponding applets have the same data when all appropriate message have been processed.
  • [0077]
    A general tool for handling update conflicts is described as the XFORM function. The XFORM function is intended to describe a broad category of functions that have the properties that are described below. In the following description
  • XFORM(A, P)={A_40 , P′},
  • [0078]
    where A and P refer to the original applet and pod messages, respectively. Messages A′ and P′ have the property that if the applet applies A followed by P′, and the pod applies P followed by A′, the applet and the pod will be in the same state.
  • [0079]
    In the update conflict example of FIG. 5, the following transform is an example of the transform that can be applied. XFORM ( del x , del y ) = { del x - 1 , del y } if x > y ; { del x , del y - 1 } if x < y ; and { no - op , no - op } if x = y .
  • [0080]
    In other words, later indexes in a string are modified to account for earlier deletions.
  • [0081]
    [0081]FIG. 6 is one embodiment of a state space for an applet and a pod while processing messages. Each node is labeled with the number of applet and pod messages processed when in that state. Solid lines indicate the applet path and dotted lines indicate the pod path. For example, if the applet is in state (2,3), the applet has processed two of its own messages and three messages from the corresponding pod. In the example of FIG. 6, a conflict occurs starting from state (1,1).
  • [0082]
    As messages are processed, the applet and pod move through the state space of FIG. 6. If the applet and pod process messages in the same order, no conflicts occur and the applet and pod take the same path (e.g., (0,0) to (1,0) to (1,1)). In the example, of FIG. 6, the applet and pod process different messages while in state (1,1). As a result, the applet moves to state (2,1) and the pod moves to state (1,2). To resolve the conflict of being in different states, both the applet and the pod process the message from the other party with the appropriate XFORM function.
  • [0083]
    Processing messages with the XFORM function moves both the applet and the pod to state (2,2). The applet and pod both process a message from the pod to move to state (2,3). Thus, as the applet and pod states diverge, the XFORM function(s) are used to reconcile the messages processed so that the applet and the pod move to the same state.
  • [0084]
    The messaging protocol of the present invention labels each message with the state of the sender just prior to when the message was generated. These labels are used to detect conflicts and the XFORM function(s) are used to resolve the conflicts. The messaging protocol guarantees that when an applet and pod reach the same state, all objects will have identical values.
  • [0085]
    The XFORM function takes a pair of applet and pod messages that were generated from the same starting state and returns transformed messages that allow the applet and the pod to reach the same final state. When the applet and pod diverge by only a single state the XFORM function can be used directly. However, when the applet and pod diverge by more than one state, reconciliation is more complex and the XFORM function cannot be used directly.
  • [0086]
    [0086]FIG. 7 is one embodiment of a state space in which an applet and a pod diverge by more than one state. In the example of FIG. 7, the applet has executed A to move to state (1,0) then receives a conflicting P1 message from the pod. The applet uses the XFORM function to generate P1′ to get to state (1,1).
  • [0087]
    The pod then generates P2 from state (0,1), which indicates that the pod has not yet processed A. The applet cannot use XFORM(A, P2) because A and P2 were not generated from the same starting state. For example using the XFORM function described above, if A is DEL4, P1 is DEL1, and P2 is DEL3, then the correct transform for P2 is NO_OP; however XFORM(A, P2) is DEL3.
  • [0088]
    In the example of FIG. 7, when the applet computes P1′, it also computes and stores A′, both of which are returned by the XFORM function. A′ represents a hypothetical message that the applet would have generated to move from state (0,1) to (1,1).
  • [0089]
    When P2 arrives, the applet uses A′ to compute XFORM(A′, P2)={A″, P2′}. The applet executes P2′ to get to state (1,2). If the pod has processed the applet's message, the pod will be in state (1,2) also. If not, the next message will originate from (0,3), not shown in FIG. 7. For this reason, the applet stores A″. This process continues until the applet and the pod are in the same state.
  • [0090]
    [0090]FIG. 8 is one embodiment of a flow diagram for sending a message. The message is described in terms of being sent from an applet to a pod; however, messages sent from the pod to the applet are processed in the same manner. For purposes of explanation, the example of FIG. 8 assumes that the pod was last known in state (x, y) and has sent k messages, leaving the pod in state (x+k, y). These messages are kept in the outgoing queue. In the flow diagrams of FIGS. 8 and 9, MyMsgs refers to the number of messages processed by the generating object and OtherMsgs refers to the number of messages received and processed. For the applet, MyMsgs is x+k and OtherMsgs is y.
  • [0091]
    In step 810 the operation is performed locally by the applet to move the applet to state (x+k, y+1). In step 820, the operation along with MyMsgs and OtherMsgs is sent to the pod. In step 830, the message sent to the pod is added to the outgoing message queue of the applet. In step 840, MyMsgs is incremented.
  • [0092]
    [0092]FIG. 9 is one embodiment of a flow diagram for receiving a message. The example of FIG. 9 assumes the same starting state as the example of FIG. 8. Thus, the next message received must originate from one of the states between (x, y) and (x+k, y), inclusive. Assuming that the pod has processed an arbitrary number (i) of the k applet messages, the received message comes from state (x+i, y), which takes the pod to state (x+i, y+1).
  • [0093]
    In step 910 a message is received. Step 920 operates to remove the messages saved by the applet that take the applet from state (x, y) to (x+i, y) because those messages have been processed by the pod and are no longer necessary to implement hypothetical messages to reconcile divergent states. In step 930, the incoming message is transformed, if necessary, with respect to the saved messages as described above. In one embodiment, any messages transformed are saved as transformed messages.
  • [0094]
    The result of step 930 is a message that takes the applet from state (x+k, y) to (x+k, y+1). In step 940 the message resulting from step 930 is applied locally. In step 950, the operation is broadcast to corresponding active applets. In step 960, OtherMsgs is incremented. The steps of FIG. 9 result in a saved sequence of messages that takes the applet from the last known pod state, (x+i, y+1) to the current state, (x+k, y+1).
  • [0095]
    In one embodiment, messages are saved until the messages are acknowledged by the corresponding pod/applet in order to transform incoming messages properly. Acknowledgements can be piggy-backed on outgoing messages. If messages are one-sided, explicit acknowledgements can be generated.
  • [0096]
    By applying concurrency control between an applet and a pod and having the pod broadcast incoming messages to other applets, a two-way concurrency control protocol can be used to provide n-way concurrency control. Each applet individually communicates messages that are processed via a two-way protocol and the results are broadcast to other applets behaving in the same manner.
  • [0097]
    Summary
  • [0098]
    Optimistic concurrency control is well suited for use with lightweight asynchronous messaging because the applet/pod generating a message is free to continue operation without waiting for a response from the receiving pod/applet. Thus, combination of optimistic concurrency control and lightweight asynchronous messaging provides objects with more natural, real-time response than would otherwise be possible.
  • [0099]
    Collaborative objects allow intelligence to be included in the applets so that operations can be performed without generating messages to a pod. Thus, collaborative objects further improve the natural, real-time response that can be provided by objects as compared to the prior art. Transparent object serialization provides persistence that allows a user to use an object without the need to manually save or otherwise be concerned with saving the state of an object. Transparent object serialization can also reduce data losses should computer systems crash or otherwise lose state that has not been saved.
  • [0100]
    In the foregoing specification, the present invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US5206934 *Aug 15, 1989Apr 27, 1993Group Technologies, Inc.Method and apparatus for interactive computer conferencing
US5241625 *Nov 27, 1990Aug 31, 1993Farallon Computing, Inc.Screen image sharing among heterogeneous computers
US5434994 *May 23, 1994Jul 18, 1995International Business Machines CorporationSystem and method for maintaining replicated data coherency in a data processing system
US5541911 *Oct 12, 1994Jul 30, 19963Com CorporationRemote smart filtering communication management system
US5588117 *May 23, 1994Dec 24, 1996Hewlett-Packard CompanySender-selective send/receive order processing on a per message basis
US5613124 *Jun 7, 1995Mar 18, 1997Microsoft CorporationMethod and system for generating and storing multiple representations of a source object in object storage
US5675796 *Aug 16, 1996Oct 7, 1997Microsoft CorporationConcurrency management component for use by a computer program during the transfer of a message
US5706502 *Mar 25, 1996Jan 6, 1998Sun Microsystems, Inc.Internet-enabled portfolio manager system and method
US5794219 *Feb 20, 1996Aug 11, 1998Health Hero Network, Inc.Method of conducting an on-line auction with bid pooling
US5796396 *Jun 5, 1997Aug 18, 1998Mitsubishi Electric Information Technology Center America, Inc.Multiple user/agent window control
US5812749 *Dec 27, 1996Sep 22, 1998Mci Communication CorporationMethod of and system for testing network time protocol client accuracy
US5844553 *Mar 29, 1996Dec 1, 1998Hewlett-Packard CompanyMechanism to control and use window events among applications in concurrent computing
US5890963 *Sep 30, 1996Apr 6, 1999Yen; WeiSystem and method for maintaining continuous and progressive game play in a computer network
US5906598 *Nov 22, 1995May 25, 1999Baxter International Inc.Self-priming drip chamber with extended field of vision
US5907598 *Feb 20, 1997May 25, 1999International Business Machines CorporationMultimedia web page applications for AIN telephony
US5916302 *Dec 6, 1996Jun 29, 1999International Business Machines CorporationMultimedia conferencing using parallel networks
US5918229 *Mar 28, 1997Jun 29, 1999Mangosoft CorporationStructured data storage using globally addressable memory
US5922044 *Jun 12, 1997Jul 13, 19993Com CorporationSystem and method for providing information to applets in a virtual machine
US5924116 *Apr 2, 1997Jul 13, 1999International Business Machines CorporationCollaborative caching of a requested object by a lower level node as a function of the caching status of the object at a higher level node
US5935249 *Feb 26, 1997Aug 10, 1999Sun Microsystems, Inc.Mechanism for embedding network based control systems in a local network interface device
US5944791 *Oct 4, 1996Aug 31, 1999Contigo Software LlcCollaborative web browser
US5959621 *Dec 6, 1996Sep 28, 1999Microsoft CorporationSystem and method for displaying data items in a ticker display pane on a client computer
US5964660 *Jun 18, 1997Oct 12, 1999Vr-1, Inc.Network multiplayer game
US5974441 *Dec 6, 1996Oct 26, 1999International Business Machines CorporationWWW client server interactive system method with Java (™)
US6018343 *Sep 27, 1996Jan 25, 2000Timecruiser Computing Corp.Web calendar architecture and uses thereof
US6023685 *May 23, 1997Feb 8, 2000Brett; Kenton F.Computer controlled event ticket auctioning system
US6029175 *Jun 7, 1996Feb 22, 2000Teknowledge CorporationAutomatic retrieval of changed files by a network software agent
US6044205 *Feb 29, 1996Mar 28, 2000Intermind CorporationCommunications system for transferring information between memories according to processes transferred with the information
US6044218 *Jan 31, 1997Mar 28, 2000Sun Microsystems, Inc.System, method and article of manufacture for creating a live application or applet development environment
US6065051 *Apr 15, 1998May 16, 2000Hewlett-Packard CompanyApparatus and method for communication between multiple browsers
US6075863 *Aug 9, 1996Jun 13, 2000Encanto NetworksIntelligent communication device
US6094673 *Jan 16, 1998Jul 25, 2000Aspect CommunicationsMethod and apparatus for generating agent scripts
US6108687 *Mar 2, 1998Aug 22, 2000Hewlett Packard CompanySystem and method for providing a synchronized display to a plurality of computers over a global computer network
US6128648 *Nov 23, 1994Oct 3, 2000International Business Machines CorporationInformation handling system and method for maintaining coherency between network servers and mobile terminals
US6195685 *May 22, 1998Feb 27, 2001International Business Machines CorporationFlexible event sharing, batching, and state consistency mechanisms for interactive applications
US6253228 *Mar 31, 1997Jun 26, 2001Apple Computer, Inc.Method and apparatus for updating and synchronizing information between a client and a server
US6289461 *Jun 9, 1998Sep 11, 2001Placeware, Inc.Bi-directional process-to-process byte stream protocol
US6338086 *Jun 11, 1998Jan 8, 2002Placeware, Inc.Collaborative object architecture
US6339826 *May 5, 1998Jan 15, 2002International Business Machines Corp.Client-server system for maintaining a user desktop consistent with server application user access permissions
US6496870 *Jan 31, 1997Dec 17, 2002Sun Microsystems, Inc.System, method and article of manufacture for collaboration with an application
US6560707 *Jan 16, 1996May 6, 2003Xerox CorporationMultimedia coordination system
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US6691157Feb 6, 2002Feb 10, 2004Citrix Systems, Inc.Method and apparatus for making a hypermedium interactive
US6983020Mar 25, 2002Jan 3, 2006Citrix Online LlcMethod and apparatus for fast block motion detection
US7152220 *Dec 9, 2000Dec 19, 2006Sensemaking Technologies Corp.Collaboration engine: adding collaboration functionality to computer software
US7163272Jun 10, 2004Jan 16, 2007Lexmark International, Inc.Inkjet print head
US7359953Oct 20, 2003Apr 15, 2008Citrix Systems, Inc.Methods and apparatus for making a hypermedium interactive
US7792971Dec 8, 2005Sep 7, 2010International Business Machines CorporationVisual channel refresh rate control for composite services delivery
US7797403Jul 12, 2002Sep 14, 2010Microsoft CorporationDeployment of configuration information
US7809838Dec 8, 2005Oct 5, 2010International Business Machines CorporationManaging concurrent data updates in a composite services delivery system
US7827288Dec 8, 2005Nov 2, 2010International Business Machines CorporationModel autocompletion for composite services synchronization
US7921158Mar 27, 2007Apr 5, 2011International Business Machines CorporationUsing a list management server for conferencing in an IMS environment
US7937370Feb 21, 2007May 3, 2011Axeda CorporationRetrieving data from a server
US7966418Feb 20, 2004Jun 21, 2011Axeda CorporationEstablishing a virtual tunnel between two computer programs
US8005934Dec 8, 2005Aug 23, 2011International Business Machines CorporationChannel presence in a composite services enablement environment
US8024407Oct 17, 2007Sep 20, 2011Citrix Systems, Inc.Methods and systems for providing access, from within a virtual world, to an external resource
US8046699 *Aug 29, 2008Oct 25, 2011Rosebud Lms, Inc.Method and software for enabling N-way collaborative work over a network of computers
US8055758Aug 14, 2006Nov 8, 2011Axeda CorporationReporting the state of an apparatus to a remote computer
US8060886Feb 12, 2007Nov 15, 2011Axeda CorporationXML scripting of SOAP commands
US8065397Dec 26, 2006Nov 22, 2011Axeda Acquisition CorporationManaging configurations of distributed devices
US8090793Mar 25, 2008Jan 3, 2012Citrix Systems, Inc.Methods and apparatus for making a hypermedium interactive
US8108543Apr 17, 2002Jan 31, 2012Axeda CorporationRetrieving data from a server
US8190679 *May 27, 2004May 29, 2012Adobe Systems, IncorporatedReal-time meeting object extensibility
US8200764 *Dec 19, 2006Jun 12, 2012International Business Machines CorporationSystem and method for achieving highly scalable real-time collaboration applications using HTTP
US8200828Oct 30, 2009Jun 12, 2012Citrix Systems, Inc.Systems and methods for single stack shadowing
US8229938Apr 3, 2009Jul 24, 2012Landmark Graphics CorporationSystems and methods for correlating meta-data model representations and asset-logic model representations
US8230096Jan 14, 2005Jul 24, 2012Citrix Systems, Inc.Methods and systems for generating playback instructions for playback of a recorded computer session
US8259923Feb 28, 2007Sep 4, 2012International Business Machines CorporationImplementing a contact center using open standards and non-proprietary components
US8285782Sep 23, 2011Oct 9, 2012Citrix Systems, Inc.Methods and apparatus for making a hypermedium interactive
US8291039May 11, 2011Oct 16, 2012Axeda CorporationEstablishing a virtual tunnel between two computer programs
US8296441Oct 30, 2009Oct 23, 2012Citrix Systems, Inc.Methods and systems for joining a real-time session of presentation layer protocol data
US8370479Oct 3, 2006Feb 5, 2013Axeda Acquisition CorporationSystem and method for dynamically grouping devices based on present device conditions
US8406119Sep 29, 2006Mar 26, 2013Axeda Acquisition CorporationAdaptive device-initiated polling
US8422851Jan 11, 2010Apr 16, 2013Citrix Systems, Inc.System and methods for automatic time-warped playback in rendering a recorded computer session
US8554778Jun 21, 2012Oct 8, 2013Landmark Graphics CorporationSystems and methods for correlating meta-data model representations and asset-logic model representations
US8578280Sep 9, 2011Nov 5, 2013Rosebud Lms, Inc.Method and software for enabling N-way collaborative work over a network of computers
US8594305Mar 9, 2007Nov 26, 2013International Business Machines CorporationEnhancing contact centers with dialog contracts
US8606768 *Dec 20, 2007Dec 10, 2013Accenture Global Services LimitedSystem for providing a configurable adaptor for mediating systems
US8615159Sep 20, 2011Dec 24, 2013Citrix Systems, Inc.Methods and systems for cataloging text in a recorded session
US8752074Oct 4, 2011Jun 10, 2014Axeda CorporationScripting of soap commands
US8769095Dec 26, 2012Jul 1, 2014Axeda Acquisition Corp.System and method for dynamically grouping devices based on present device conditions
US8788632Oct 4, 2011Jul 22, 2014Axeda Acquisition Corp.Managing configurations of distributed devices
US8898294Oct 3, 2011Nov 25, 2014Axeda CorporationReporting the state of an apparatus to a remote computer
US8935316Oct 30, 2009Jan 13, 2015Citrix Systems, Inc.Methods and systems for in-session playback on a local machine of remotely-stored and real time presentation layer protocol data
US9002980Sep 13, 2012Apr 7, 2015Axeda CorporationEstablishing a virtual tunnel between two computer programs
US9055150Mar 1, 2007Jun 9, 2015International Business Machines CorporationSkills based routing in a standards based contact center using a presence server and expertise specific watchers
US9130936 *Oct 2, 2009Sep 8, 2015Pulse Secure, LlcMethod and system for providing secure access to private networks
US9170902Feb 20, 2013Oct 27, 2015Ptc Inc.Adaptive device-initiated polling
US9247056Mar 1, 2007Jan 26, 2016International Business Machines CorporationIdentifying contact center agents based upon biometric characteristics of an agent's speech
US9444791Jul 30, 2015Sep 13, 2016Pulse Secure, LlcMethod and system for providing secure access to private networks
US9491049Jul 18, 2014Nov 8, 2016Ptc Inc.Managing configurations of distributed devices
US9491071Jun 27, 2014Nov 8, 2016Ptc Inc.System and method for dynamically grouping devices based on present device conditions
US9591065Jun 6, 2014Mar 7, 2017Ptc Inc.Scripting of SOAP commands
US9614879Nov 4, 2013Apr 4, 2017Rosebud Lms, Inc.Method and software for enabling N-way collaborative work over a network of computers
US9674067Oct 23, 2015Jun 6, 2017PTC, Inc.Adaptive device-initiated polling
US9712385Apr 6, 2016Jul 18, 2017PTC, Inc.Managing configurations of distributed devices
US20020107994 *Dec 9, 2000Aug 8, 2002Rickards William S.Collaboration engine: adding collaboration functionality to computer software
US20030179951 *Mar 25, 2002Sep 25, 2003Christiansen Bernd O.Method and apparatus for fast block motion detection
US20040010429 *Jul 12, 2002Jan 15, 2004Microsoft CorporationDeployment of configuration information
US20040139117 *Oct 20, 2003Jul 15, 2004Jeff MuirMethods and apparatus for making a hypermedium interactive
US20060039477 *Oct 18, 2005Feb 23, 2006Christiansen Bernd OMethod and apparatus for fast block motion detection
US20070103498 *Nov 14, 2006May 10, 2007Parish George KInkjet printhead
US20080147834 *Dec 19, 2006Jun 19, 2008Quinn William MSystem and method for achieving highly scalable real-time collaboration applications using http
US20090077474 *Aug 29, 2008Mar 19, 2009Rosebud Lms, Inc.Method and Software for Enabling N-Way Collaborative Work Over a Network of Computers
US20090106347 *Oct 17, 2007Apr 23, 2009Citrix Systems, Inc.Methods and systems for providing access, from within a virtual world, to an external resource
US20090164500 *Dec 20, 2007Jun 25, 2009Ankur MathurSystem for providing a configurable adaptor for mediating systems
US20090183087 *Dec 7, 2008Jul 16, 2009Binfire CorpoartionMethod and Apparatus for Real Time Image Transfer Between Two or More Computers
US20090254569 *Mar 13, 2009Oct 8, 2009Landmark Graphics Corporation, A Halliburton CompaSystems and Methods for Real Time Data Management in a Collaborative Environment
US20100005111 *Apr 3, 2009Jan 7, 2010Landmark Graphics Corporation, A Halliburton CompanySystems and Methods for Correlating Meta-Data Model Representations and Asset-Logic Model Representations
US20100049795 *Oct 2, 2009Feb 25, 2010Juniper Networks, Inc.Method and system for providing secure access to private networks
US20110106856 *Mar 13, 2009May 5, 2011Landmark Graphics Corporation, A Halliburton CompanySystems and Methods for Real Time Data Management in a Collaborative Environment
EP1381186A1 *Jul 2, 2003Jan 14, 2004Microsoft CorporationDeployment of configuration information
Classifications
U.S. Classification709/218, 719/315
International ClassificationH04L29/06, H04L29/08, G06F15/16, G06F9/46
Cooperative ClassificationH04L67/10, H04L67/38, H04L69/329, H04L67/42, H04L29/06
European ClassificationH04L29/08N9, H04L29/06
Legal Events
DateCodeEventDescription
Jan 15, 2015ASAssignment
Owner name: MICROSOFT TECHNOLOGY LICENSING, LLC, WASHINGTON
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MICROSOFT CORPORATION;REEL/FRAME:034766/0001
Effective date: 20141014