摘要:
A packet filter can be programmed by a remote controller to detect packets meeting a particular criterion and to report detection of these packets to the controller. The reports from the packet filter are collected and analyzed by the remote controller. A streams module that incorporates the packet filter is used within a Solaris operating system environment that has been enhanced to support an object framework. The streams module exports a programming interface to the packet filter defined in an interface definition language (IDL). The streams module can be pushed onto a network device in a similar fashion to other streams modules. The streams module responds to requests from one remote controller or to requests from more than one remote controller. These remote controller requests arrive as remote procedure call (RPC) requests on the IDL object references exported by the module. The packet filter within the streams module is fully programmable, and it collects and returns information to the controller through a call back object on the controller. The particular traces collected can be configured dynamically by the controller, by issuing RPC requests to the packet filters through the IDL interfaces. Alternately, a standard Solaris environment can be used. In such a case, a standard (i.e., non-object oriented) RPC approach is employed. Furthermore, the above approach will work with other UNIX systems that support stream modules. Moreover, because other operating systems have streams-like input/output capabilities, the approach can be extended to non-UNIX systems such as DOS, Windows NT, OS/2 Warp or the Macintosh operating system.
摘要:
A bit map is maintained by a provider object of a name server to keep track of names cached by a cache object of the client. The bit map is indexed by performing a hash of the name. When a name is looked up by the server on behalf of a client, the server hashes the name, and sets the bit in the bit map indexed by the result of the hash modulo the size of the bit map. The result of the hash is returned to the client and is stored with the entry in the cache. A bit "set" in the bit map indicates that the client caches at least one name that hashes into the bit. When the server invalidates a name, a hash of the name to be invalidated is used to find the corresponding bit in the bit mask. If the bit is set, the server sends an invalidation request to the client. The invalidation request includes the result of the hash, and the size of the provider's bit map. The client invalidates all entries that hash into the specified bit in the bitmap on the server. Alternatively, the invalidation request also includes the name to be invalidated and the client invalidates only the entry that matches the name.
摘要:
Transparent routing within the cluster is achieved (without changing the networking code on each node of the cluster) by using a pair of modules interposed appropriately on the networking stack. In a "clustered" system built out of several computers, using the present invention, the networking subsystem appears to applications as if the applications are running on a single computer. In addition, no modifications to the networking code is needed. The present invention is extensible to a variety of networking protocols, not just TCP/IP as the packet filter allows the routing within the cluster to be done dynamically. No modifications to the applications is needed (same binaries will work). A packet filter and remote communication between the modules through IDL enable the modules to do their job. A name server that maintains the port name space is used.
摘要:
One embodiment of the present invention provides a method and an apparatus that facilitates transparent failovers from a primary copy of an object on a first server to a secondary copy of the object on a second server when the first server fails, or otherwise becomes unresponsive. The method includes detecting the failure of the first server; selecting the second server; and reconfiguring the second server to act as a new primary server for the object. Additionally, the method includes transparently retrying uncompleted invocations to the object to the second server, without requiring explicit retry commands from a client application program. A variation on this embodiment further includes winding up active invocations to the object before reconfiguring the second server to act as the new primary server. This winding up process may include causing invocations to unresponsive nodes to unblock and complete. Another variation includes blocking new invocations to the object after detecting the failure of the first server, and unblocking these new invocations after reconfiguring the second server to act as the new primary server. Hence, the present invention can greatly simplify programming of client application programs for highly available systems. It also makes it possible to use a client application program written for a nonhighly available system in a highly available system.
摘要:
The resources needed by an application to execute are declared by the application. When the application is activated, only the declared resources are made available to the application because only the declared resources are connected to the execution environment. Accessibility to resources may be controlled by the operating system by making the resource visible or invisible to the executing software by mapping a local name used by the executing software to a global resource, possibly limiting the type of access allowed. Because the executing software relies on the mapping function performed by the operating system for access to resources, and the operating system only maps names declared by the software, the operating system can isolate the software, and prevent the application from accessing undeclared global resources.
摘要:
Reference counting is shared between an in-process service runtime and a machine-wide service. The service maintains a global reference count, a global export count, and an exports before revoke count. When the global reference count for a resource or object drops to zero, the machine-wide service deletes the table entry for the object or resource and sends an unref message including the value of the global export count to the sharing process. If the local export count is greater than the global export count of the unref, there are committed exports which have not yet been unreferenced. If both counts are the same, the committed exports have been accounted for and a revoke operation can be issued.
摘要:
When a process running in an isolated execution environment is started by a user, the credentials of the user are associated with a naming environment for the isolated execution environment. The isolated execution environment may be implemented via creation of a namespace representing resources available to one or more processes running within the isolated execution environment. The resources available to the isolated processes may represent some subset of global resources. When a request to access a named resource is received, the request is mediated by the operating system. Access, if provided, may be provided via the naming environment associated with the isolated execution environment. The operating system determines whether to grant or deny access to the resource by checking the credentials associated with the naming environment with the ACL of the resource.
摘要:
Embodiments described herein are directed to updating the various software associated with a distributed application in a piecemeal fashion. All instances of the software are analyzed and separated into different portions, called “roles.” Each instance of a role is strategically assigned to an update domain based on the structural information included in the service model of the distributed application. The distributed application is upgraded one update at a time by selecting an update or host update domain, bringing the roles assigned thereto offline, updating the offline roles, bringing the roles back online, and repeating for other update or host update domains.
摘要:
An operating system architecture is based on a service model in which active entities (services) are containers for objects having a number of interfaces specified through a contract language that is a subset of the language in which the service is coded. Services may reside in the same address space or may reside in separate address spaces, without changing the programming model or compiled binaries. The location of a service is independent of the location of the service's clients and of services the service calls.
摘要:
Object invocation may be carried out by one thread in a service which may include multiple executing threads. In a mechanism for implementing a cancellation operation in a cooperative system, a thread identifies an operation to be cancelled. A cancel function has an argument comprising the thread identifier in which the operation is to be cancelled. The cancel function is called by a client process thread to cancel a pending object invocation initiated by the client process. An immediate or hard cancel causes the targeted client and cancel thread to return immediately. A discretionary or soft cancel does not affect the targeted client thread. In either case the server process is notified via a maintenance notification. The target thread of the cancel cannot be reused for other work until the cancel request or notification has returned.