Abstract: A system and method for providing process persistence in a virtual machine are described. A virtual persistent heap may be provided. The virtual persistent heap may enable the checkpointing of the state of the computation of a virtual machine, including processes executing within the virtual machine, to a persistent storage such as a disk or flash device for future resumption of the computation from the checkpoint. The Virtual Persistent Heap also may enable the migration of the virtual machine computation states, and thus the migration of executing processes, from one machine to another. The saved state of the virtual machine heap may also provide the ability to restart the virtual machine after a system crash or shutdown to the last saved persistent state, and to thus restart a process that was running within the virtual machine prior to the system crash or shutdown to a checkpointed state of the process stored in the virtual persistent heap.

Abstract: Embodiments of message gates are described. A message gate is the message endpoint for a client or service in a distributed computing environment. A message gate may provide a secure endpoint that sends and receives type-safe messages. Gates may perform the sending and receiving of messages between clients and services using a protocol specified in a service advertisement. In one embodiment, the messages are eXtensible Markup Language (XML) messages. For a client, a message gate represents the authority to use some or all of a service's capabilities. Each capability may be expressed in terms of a message that may be sent to the service. Creation of a message gate may involve an authentication service that generates an authentication credential, and that may negotiate the desired level of security and the set of messages that may be passed between client and service. A message gate may perform verification of messages against a message schema to ensure that the messages are allowed.

Abstract: In a distributed computing environment, a message gate may be the message endpoint for a client or service to communicate with another client or service. Devices may have a gate factory (e.g. message endpoint constructor) that is trusted code on the device for generating gates based on XML message descriptions. The use of the gate factory may ensure that the gate it generates is also trusted code, and that the code is correct with respect to a service advertisement. A service advertisement may indicate, for a particular service, a message schema, service URI and authentication service URI. In one embodiment, the pieces the gate factory needs to construct a gate are the XML schema of the service and the URI of the service. In another embodiment, an authentication credential may also be obtained and used in gate construction by running an authentication service specified in the service advertisement.

Abstract: A cluster implements a virtual disk system that provides each node of the cluster access to each storage device of the cluster. The virtual disk system provides high availability such that a storage device may be accessed and data access requests are reliably completed even in the presence of a failure. To ensure consistent mapping and file permission data among the nodes, data are stored in a highly available cluster database. Because the cluster database provides consistent data to the nodes even in the presence of a failure, each node will have consistent mapping and file permission data. A cluster transport interface is provided that establishes links between the nodes and manages the links. Messages received by the cluster transports interface are conveyed to the destination node via one or more links. The configuration of a cluster may be modified during operation.

Abstract: A message gate is the message endpoint for a client or service in a distributed computing environment. A message gate may provide a secure message endpoint that sends and receives type-safe messages. A gate may have a gate name that is a unique ID that refers only to the gate. In one embodiment, a gate is assigned a gate name when the gate is created and the gate name refers to only that gate for the life of the gate. A gate may be addressed using its gate name. The name may allow clients and services to migrate about the network and still work together. In a preferred embodiment, the gate address is independent of the physical message transport address and/or socket layer. Thus, a gate name may provide a virtual message endpoint address that may be bound and un-bound to a message transport address.

Abstract: A system and method for searching for Internet-based repositories within a distributed computing environment are provided. A client on a device may interact with a search service on the same or a different device to find spaces (i.e., network-accessible XML object repositories) for storage and/or retrieval of data. The client may send an XML search request to the search service. The search request may include one or more desired characteristics, such as keywords, which are sought of a space. Based upon the search request, the search service may generate search results including locations (e.g., URIs) of one or more resulting spaces. The spaces may include web pages. In generating the search results, the search service may interact with a network-accessible third-party search engine, such as a browser-accessible search engine. The search service may obtain a service advertisement for each of the resulting spaces. Each service advertisement includes information which is usable to access the respective space.

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: A method and system for garbage collecting a virtual heap using nursery regions for newly created objects to reduce flushing of objects from an in-memory heap to a store heap 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.

Abstract: A caching mechanism for a virtual persistent heap is described. 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. All references may be kept in one address space, the virtual persistent heap address space.

Abstract: Various embodiments of a system and method related to location-independent message addressing for a computer network are disclosed. According to one embodiment, a plurality of nodes, e.g., computer systems, may be connected to a network. The plurality of nodes may include a first node which is operable to send a message addressed using a “role”. The role may be associated with one or more other nodes coupled to the network. The message may be sent to each of the one or more nodes with which the role is associated without specifying locations of the one or more nodes. For example, the role may have an associated name, and the message may be addressed using the role name.

Abstract: Methods and apparatus for a cooperative processing of a task in a multi-threaded computing system are disclosed. In one aspect of the invention, a first thread is arranged to receive a task and only partially process the task. During its processing, the first thread stores processing information that is relevant to future processing in a packet that is associated with the task. Upon completing its processing, the first thread designates a second thread as the owner of the packet. After the second thread obtains ownership of the packet it then further processes the task based at least in part upon the processing information stored in the packet by the first thread. With the described arrangement no synchronization primitives are required for the threads to cooperate in processing the task.

Abstract: A system and method for searching for documents within spaces in a distributed computing environment are provided. A client sends a lookup message to a space which stores documents. The lookup message may specify desired characteristics, such as a name or partial XML schema, of the stored documents. The documents may include XML service advertisements and XML device advertisements as well as general-purpose XML documents. A set of zero or more documents which match the lookup message are discovered. In one embodiment, the lookup message may include a desired name. If the lookup message includes both a desired name and a desired schema, the set of discovered documents may include both discovered documents having a name that matches the desired name and discovered documents having a schema that matches the desired schema. If the lookup message includes neither a desired name nor a desired schema, the set of discovered documents may include substantially all the documents stored in the space.

Abstract: A method and system for providing an intelligent intermediate form of an object-oriented database. The intermediate form is derived from a grammatical form of an object-oriented database through the process of compilation. The grammatical form is a persistent form of an object-oriented database expressed in a human-readable and human-editable textual form according to a grammar. The intermediate form comprises an array of intelligent entry objects which encapsulate data with methods for manipulating that data. The methods include creating a database entry, creating a property associated with an entry, creating an attribute associated with an entry or property, querying the last entry, property, or attribute created, and finalizing entry storage. The intermediate form lacks the infrastructure of the database, but the intermediate form can be used to populate the object-oriented database with entries.

Abstract: A method and system for customizing the transformation of an object-oriented database to and from a grammatical form. A grammatical form is an expression of an object-oriented database in a textual form according to a grammar. The transformation customizer is a plug-in which provides translation of primitive data types to and from complex data types for compilation and serialization processes. A complex data type is defined in terms of one or more primitive data types. One or more values in the object-oriented database are expressed in terms of the complex data type. During serialization, the plug-in module is invoked. The plug-in understands both the complex data type and the primitive data types. The values from the object-oriented database are translated from the complex data type to the primitive data types. For customizing compilation, one or more values expressed in terms of the primitive data types are translated to the complex data type when the plug-in is invoked.

Abstract: A method and system for serializing a transient object-oriented database into a persistent form. The persistent form is a grammatical form, an expression of an object-oriented database in a textual form according to a grammar. The grammatical form is human-readable and human-editable. The grammar is designed to be platform-independent and programming-language-independent and therefore descriptive of any hierarchical object-oriented database. An object-oriented database is expressed as a plurality of entries in a transient, hierarchical, object-oriented form. The tree of entries is navigated and each entry is written to the persistent form as text according to the grammar. The serialized form stores only the key state of the database, not a “snapshot” of memory. Therefore, the persistent, serialized form is smaller than the in-memory, transient form of the object-oriented database.

Abstract: Methods and apparatus for implementing a core application programming interface which is a part of more than one application programming interface are disclosed. According to one aspect of the present invention, a class structure in an object based system is arranged to provide application programming interfaces which enable access to a system database. The class structure includes a first set of classes that define a core application programming interface, a second set of classes that define a client application programming interface, and a third set of classes that define a server application programming interface. The second set of classes includes the first set of classes, and the third set of classes includes the second set of classes. In one embodiment, the first set of classes includes interfaces.

Abstract: A method and system for compiling a grammatical form of an object-oriented database into an intermediate form of that database. The grammatical form is a persistent form of an object-oriented database expressed in a human-readable and human-editable textual form according to a grammar. The textual form is parsed into a series of tokens. The tokens are compiled into a plurality of entries. The plurality of entries are expressed in an intermediate form. The intermediate form comprises an array of intelligent entry objects which encapsulate data with methods for manipulating that data. The methods include creating a database entry, creating a property associated with an entry, creating an attribute associated with an entry or property, querying the last entry, property, or attribute created, and finalizing entry storage. The intermediate form lacks the infrastructure of the database, but the intermediate form can be used to populate the object-oriented database with entries.

Abstract: A grammar to represent a hierarchical object-oriented database. The grammar comprises a set of keywords and a syntax. The keywords include “tree”, “entry”, “properties”, and “attributes”. Properties and attributes are defined by name-value pairs. The grammar is designed to be platform-independent and programming-language-independent and therefore descriptive of any hierarchical object-oriented database. A grammatical form, a description of an object-oriented database in a textual form according to the grammar, may be stored in a persistent form such as one or more files on disk. The grammatical form is human-readable and human-editable. The grammatical form can be created by hand, or it can be created from an object-oriented database in transient form through the process of serialization. The grammatical form can be transformed into an object-oriented database through the process of compilation.

Abstract: A peer-to-peer platform that may provide mechanisms through which peers may discover each other, communicate with each other, and cooperate with each other to form peer groups is described. The peer-to-peer platform may comprise several layers including a peer-to-peer platform layer, a peer-to-peer services layer, and a peer-to-peer applications layer. At the highest abstraction level, the peer-to-peer platform may be viewed as a set of protocols. Each protocol may be defined by one or more messages exchanged among participants of the protocol. In one embodiment, the peer-to-peer platform may include, but is not limited to, one or more of a peer discovery protocol, a peer resolver protocol, a peer information protocol, a peer membership protocol, a pipe binding protocol, and an endpoint routing protocol. To underpin this set of protocols, the peer-to-peer platform may define a number of concepts including peer, peer group, advertisement, message, pipe, and endpoint.

Abstract: A system and method for providing an open network computing platform designed for peer-to-peer computing. The peer-to-peer platform may provide protocols for peer-to-peer services and applications that allow peers to discover each other, communicate with each other, and cooperate with each other to form peer groups. The protocols may include a peer membership protocol, a peer discovery protocol, a peer resolver protocol, a peer information protocol, a pipe binding protocol, and a peer endpoint protocol. Services and applications that participate in the protocols may be provided to deal with higher-level concepts. Advertisements may be used to publish peer resources. The peer-to-peer platform provides the ability to replicate information toward end users and may enable peers to find content that is closest to them. The peer-to-peer protocols and unique peer identifiers may allow peer nodes to move to different locations and access services and other content independent of network physical addresses.