Abstract: A system and method for providing rendezvous nodes in a peer-to-peer networking environment is described. Rendezvous nodes preferably cache information about network resources that may be useful to peer nodes on a peer-to-peer network. In one embodiment, a network of rendezvous nodes may help peer nodes to discover network resources over long-range on the peer-to-peer network. Network resource may include, but may not be limited to peer nodes, peer groups, services, content, and communication channels. In one embodiment, rendezvous nodes may respond to discovery query messages from peer nodes. The discovery query messages may specify desired network resource information. In one embodiment, rendezvous nodes may provide route discovery for network resources. In one embodiment, a peer node may be pre-configured with a pre-defined set of rendezvous nodes to access on startup. These bootstrapping rendezvous may help the peer node discover network resources that it needs to start up.

Abstract: A data representation language representation of the state of a process executing on a client or service in a distributed computing environment may be created. The representation may include a computation state of the device and/or virtual machine on which the process is executing, wherein the computation state of the device and/or virtual machine comprises information about the execution state of the process on the device and/or virtual machine. A process state may include, but is not limited to: threads, all objects referenced by the threads, transient variables created during the execution of the process, objects and their data, etc. In one embodiment, data describing one or more leases representing grants of access to external services, obtained from spaces by the process, may also be stored with the process state. The data representation language representation of the state of a process may be moved from node to node within the distributed computing environment.

Abstract: Embodiments of a decentralized mechanism for detecting the presence of entities in a peer-to-peer network. In one embodiment, using pipes, a peer may uniquely and independently generate an identity for a peer-to-peer network entity. The identity may be used to probe the peer-to-peer network for presence of instances of the corresponding entity on other peers regardless of which peer the identity was generated on and without using a central identity repository or presence system. In one embodiment, net crawling may be used to map identities and resolve the locations of instances of the corresponding entities. An entity may move anywhere on the network, and the decentralized mechanism for detecting entity presence may be used to locate the instance(s) of the entity.

Abstract: A system and method for providing message-based leasing of resources in a distributed computing environment. Services may issue leases to clients and provide operations on those leases. The lease functionality of a service may be defined in an XML message schema. Gates may be used to perform lease operations. Leases may be granted for a period that may be negotiated. Leasing messages for performing leasing operations may be defined. The leasing messages may include messages to renew a lease and to cancel a lease. Leasing messages may include embedded credentials for authenticating the sender of the message. A client may embed a credential in messages sent to the service. The service may then authenticate the credential when received in a message from the client.

Abstract: A system and method for establishing communications channels between and among peers in a peer-to-peer networking environment. Pipes may be used as communication channels for sending and receiving messages and other data between services or applications over input and output endpoints. Pipes may be asynchronous, unidirectional, stateless and unreliable. Bidirectional pipes may also be supported. Pipes may have ends that may be moved around and bound to different peers at different times. Point-to-point and propagate pipes may be supported. Pipes may connect peers that have a direct physical link and peers that do not have a direct link. Peers may communicate through pipes without knowing on which peer a pipe endpoint is bound. A message is sent to all peer endpoints currently connected (listening) to the pipe. The set of connected endpoints may be obtained from a pipe service using a pipe binding protocol.

Abstract: System and method for the dynamic and transparent migration of services in a peer-to-peer networking environment. Member peers in a peer group using a peer-to-peer platform may cooperate to provide redundant instances of services to member peers. Dynamic migration of a service may be performed by unbinding one or more peer-to-peer platform pipes from a peer hosting an instance of the service and binding the pipes to another peer hosting a different instance of the service. Using pipes, services may transparently failover from one physical peer endpoint to another in order to mask a service or peer failure, or to access a newly published instance of a service. Thus, a collection of peers may provide a high level of fault tolerance, where, for example, a new peer at a different location may replace a crashed peer, with the new peer taking over the existing pipe to keep the communication going.

Abstract: A system and method for sending, resolving, and receiving queries for information on the status of network resources. A peer computing system may include one or more resolver nodes on a network for resolving queries for a resource to particular resource instances. The resolver nodes may receive query messages from peer nodes on the network. Each query message may request information about a resource implemented by one or more peer nodes on the network. The query messages may be formatted in accordance with a peer resolver protocol. The resolver node may determine a particular instance of the resource hosted on a particular peer node to receive the query. The resolver node may use a variety of criteria to determine a particular resource instance. The resolver node may forward the query message to the determined resource instance.

Abstract: A system and method for interaction and access to shared content among clients and services in a distributed computing environment. A client may access a space service. The space service may store one or more XML service advertisements and/or other XML content in a space, and each of the service advertisements may include information which is usable to access and execute a corresponding service. The space service may include an XML schema which specifies one or more messages usable to invoke functions of the space service. For example, the schema may specify methods for reading advertisements from the space and publishing advertisements in the space. In accessing the space service, the client may send information such as an XML message (as specified in the schema) to the space service at an Internet address. In accessing the space service, the client may search the one or more service advertisements stored in the space. The client may select one of the service advertisements from the space.

Abstract: A system and method for providing resources to networked devices for participating in a peer-to-peer environment. In one embodiment, a peer computing system on a network may include one or more bootstrap nodes that may provide, to devices coupled to the network, mechanisms for accessing resources for participating in the peer-to-peer environment. The bootstrap nodes may be peer nodes. The resources may give the devices access to services each of which may implement peer-to-peer platform protocols. The devices may be pre-configured to access one or more predefined peer nodes for information on bootstrap nodes. Alternatively, devices may use a bootstrapping mechanism to locate bootstrap nodes on the network.

Abstract: Embodiments of a mechanism for providing results gates to clients in the distributed computing environment to be used by the clients to access results generated by services on behalf of the clients. A client generates a request message for a service. The request message is generated by a client method gate. The service then generates results in response to the message. A results gate is generated for accessing the results. A gate on the client generates the results gate. The results are then accessed through the results gate. The results are structured as an object (e.g. Java object), and the results gate an object proxy for the results object. The results gate is returned to the process as results of the method call made by the process. In one embodiment, the results gate is a method gate and provides a method interface to the results.

Abstract: A system and method for providing security for newly spawned spaces in a distributed computing environment. A client may access a first space service. The creation of a second space may be requested, such as by the client sending an appropriate request to an interface of the first space. In one embodiment, the first space and second space may share a common storage model, storage facility, and/or XML schema. The second space may initially be configured to permit access only to the requesting client. In one embodiment, a root authentication token is created for the second space. An authentication service associated with the second space may be initialized, whereby the second space is configured to permit access only to a client holding the root authentication token. The root authentication token may be sent to the requesting client or service. The requesting client may send the root authentication token to a second client.

Abstract: A service discovery protocol may allow clients in a distributed computing environment to search for services. Service providers (or a listener agent) may respond to search requests by publishing or providing corresponding service advertisements or URIs to corresponding service advertisements. When a service provider responds to a discovery search request (either directly or through a listener agent), the provider may choose to publish a protected or an un-protected (complete) advertisement. A protected advertisement may include the set of information necessary to obtain a complete advertisement. Publishing a protected advertisement may force the client to obtain a valid credential from an authentication service before receiving the complete un-protected advertisement from the service provider. A complete un-protected advertisement is needed to create a message endpoint for accessing the service.

Abstract: A system and method of operating a client network computer in a disconnected mode. A client computer system includes a client storage device, a processor, a network interface, a failover server and a software manager. The processor is configured to execute software instructions stored in the client storage device. The network interface is configured to connect the client computer system to a remote network server unit. A failover server implemented on the client computer system is configured to provide functionality similar to the remote network server unit by accessing a copy of a network database file stored on the client storage device. A software manager stored in the client storage device is configured to cause the client computer system to connect to the remote network server unit if the remote network server unit is available or to cause the client computer system to connect to the failover server if the remote network server unit is not available.

Abstract: A database store method and system for a virtual persistent heap may include an Application Programming Interface (API) that provides a mechanism to cache portions of the virtual heap into an in-memory heap for use by an application. The virtual heap may be stored in a persistent store that may include one or more virtual persistent heaps, with one virtual persistent heap for each application running in the virtual machine. Each virtual persistent heap may be subdivided into cache lines. The store API may provide atomicity on the store transaction to substantially guarantee the consistency of the information stored in the database. The database store API provides several calls to manage the virtual persistent heap in the store. The calls may include, but are not limited to: opening the store, closing the store, atomic read transaction, atomic write transaction, and atomic delete transaction.

Abstract: A virtual heap for a process executing within a virtual machine is described. In one embodiment, the virtual persistent heap may allow the running of an application on a physical heap that is smaller than may otherwise be required. As an example, the virtual persistent heap may be an order of magnitude larger than the physical, in-memory heap. This feature is important for small consumer and appliance devices, as these devices may have a limited amount of memory. In one embodiment, the virtual heap may be maintained on non-volatile memory storage external to the device running the virtual machine, and portions of the heap for the current execution state of the process may be cached in and out of a “physical” heap resident in local memory on the device. For example, the device may connect to a server on the Internet, and the server may provide non-volatile storage space for the virtual heap.

Abstract: A system and method for spawning new spaces in a distributed computing environment. A client may access a first space service at a first Internet address. The first space service may store one or more service advertisements and/or other content in a first space, and each of the service advertisements may include information which is usable to access and execute a corresponding service. The first space service may include a first XML schema which specifies one or more messages usable to invoke functions of the first space service. The creation of a second space may be requested such as by the client sending an appropriate request to an interface of the first space. The second space may be created to store the results of running a service. In response, a second space service with a second space may be created at a second Internet address. The second space service may include a second schema which includes at least the first schema, and the second schema may include additional functionality as well.

Abstract: A system and method for providing message-based leasing of resources in a distributed computing environment. Services may issue leases to clients and provide operations on those leases. The lease functionality of a service may be defined in an XML message schema. Gates may be used to perform lease operations. Leases may be granted for a period that may be negotiated. Leasing messages for performing leasing operations may be defined. The leasing messages may include messages to renew a lease and to cancel a lease. Services may specify an address where leasing messages may be sent. A lease renewal mechanism may be provided in which a gate may receive lease renewal messages and automatically respond to them. A mechanism to detect stale advertisements in a space may be provided. When a service publishes its advertisement in a space, the service obtains a lease on the publishing of its advertisement. Each advertisement may include a time by which the service may renew the advertisement.

Abstract: A caching mechanism for a virtual persistent heap. A feature of a virtual persistent heap is the method used to cache portions of the virtual persistent heap into the physical heap. The caching mechanism may be effective with small consumer and appliance devices that typically have a small amount of memory and that may be using flash devices as persistent storage. In the caching mechanism, the virtual persistent heap may be divided into cache lines. A cache line is the smallest amount of virtual persistent heap space that can be loaded or flushed at one time. Caching in and caching out operations are used to load cache lines into the heap or to flush dirty cache lines into the store. Different cache line sizes may be used for different regions of the heap. Translation between a virtual persistent heap address and the heap may be simplified by the caching mechanism.

Abstract: Systems and methods for returning results of services within a distributed computing environment are provided. After a client invokes one or more functions of a service, results of the function(s) may be returned to the client in a plurality of ways: for example, in a message, in a space (e.g., a network-addressable storage location), in a space wherein the client is notified via an event, using an advertisement returned in a message, using an advertisement returned in a space, and using an advertisement returned in a space wherein the client is notified via an event. The advertisement may include the information necessary to access and read the results in a storage location such as a space. A schema for the service may specify a plurality of messages which are usable to invoke the function(s) of the service. The messages, results, and advertisements may be expressed in a platform-independent and/or programming-language-independent data representation language such as XML.

Abstract: A method and system for performing generational garbage collection on a virtual heap in a virtual machine is provided. The garbage collection method is suited for use with small consumer and appliance devices that have a small amount of memory and may be using flash devices as persistent storage. The garbage collection method may provide good performance where only a portion of the virtual heap may be cached in the physical heap. The virtual heap may use a single address space for both objects in the store and the in-memory heap. In one embodiment, a single garbage collector is run on the virtual heap address space. The garbage collection method may remove non-referenced objects from the virtual heap. The garbage collection method may also include a compaction phase to reduce or eliminate fragmentation, and to improve locality of objects within the virtual heap.