State (computer science)

About: State (computer science) is a research topic. Over the lifetime, 24436 publications have been published within this topic receiving 225733 citations.

Mechanism for providing virtual machines for use by multiple users

Abstract: According to one aspect of the invention, a request to generate a state checkpoint of a computer is initiated within a user-level software entity, such as a virtual machine. Upon sensing the request, a checkpointing mechanism generates and stores at least one checkpoint, each checkpoint comprising a representation of the total state of the computer system. Upon sensing a state restoration request corresponding to one of the checkpoints, the checkpointing mechanism restores the checkpointed state in the computer, which can then resume operation from the restored total state. According to another aspect of the invention, a total checkpointed state is exported to another computer, where the state can be modified, for example, debugged, and then loaded into either the originally checkpointed computer (which, again, may be a virtual machine), or some other computer.

Current compliant sensing architecture for multilevel phase change memory

Abstract: A memory device and a method of reading the same includes a phase change element having a data state associated therewith that features maintaining the consistency of the data state of the phase change element in the presence of a read current. The memory circuit includes a sense amplifier that defines a sensing node. Circuitry selectively places the bit line in data communication with the sensing node, defining a selected bit line. A current source produces a read current, and a switch selectively applies the read current to the sensing node. Logic is in electrical communication with the sensing node to control the total energy to which the phase change material is subjected in the presence of the read current so that the data state remains consistent.

Configuring power management functionality in a processor

Abstract: In one embodiment, a multicore processor includes cores that can independently execute instructions, each at an independent voltage and frequency. The processor may include a power controller having logic to provide for configurability of power management features of the processor. One such feature enables at least one core to operate at an independent performance state based on a state of a single power domain indicator present in a control register. Other embodiments are described and claimed.

Specification and Verification of Declarative Open Interaction Models: A Logic-Based Approach

Abstract: The advent of distributed and heterogeneous systems has laid the foundation for the birth of new architectural paradigms, in which many separated and autonomous entities collaborate and interact to the aim of achieving complex strategic goals, impossible to be accomplished on their own. A non exhaustive list of systems targeted by such paradigms includes Business Process Management, Clinical Guidelines and Careflow Protocols, Service-Oriented and Multi-Agent Systems. It is largely recognized that engineering these systems requires novel modeling techniques. In particular, many authors are claiming that an open, declarative perspective is needed to complement the closed, procedural nature of the state of the art specification languages. For example, the ConDec language has been recently proposed to target the declarative and open specification of Business Processes, overcoming the over-specification and over-constraining issues of classical procedural approaches. On the one hand, the success of such novel modeling languages strongly depends on their usability by non-IT savvy: they must provide an appealing, intuitive graphical front-end. On the other hand, they must be prone to verification, in order to guarantee the trustworthiness and reliability of the developed model, as well as to ensure that the actual executions of the system effectively comply with it. In this dissertation, we claim that Computational Logic is a suitable framework for dealing with the specification, verification, execution, monitoring and analysis of these systems. We propose to adopt an extended version of the ConDec language for specifying interaction models with a declarative, open flavor. We show how all the (extended) ConDec constructs can be automatically translated to the CLIMB Computational Logic-based language, and illustrate how its corresponding reasoning techniques can be successfully exploited to provide support and verification capabilities along the whole life cycle of the targeted systems.

System and method of using annotations to optimize dynamically translated code in the presence of signals

Abstract: A method and system of dynamically translating code that uses code annotations to determine whether the dynamic translator must fully materialize machine state. At compilation time, annotations are placed in an application's executable file indicating the number of formal parameters expected by each of the application's entry points. When the application is dynamically translated, the dynamic translation system (DTS) aggressively translates the application. Therefore, the DTS does not generate instructions for materializing the machine state at potential stopping points. When the application makes a system call that arms an exception handler, the DTS looks to the annotations to determine the number of formal parameters expected by the handler. If an exception handler expects two or fewer parameters, then that handler does not use the machine state. Conversely, if a handler expects three or more parameters, then that handler may use the machine state. Therefore, if the handler only has two formal parameters, then the DTS continues to aggressively translate the application program. Otherwise, the DTS discards all of the previously translated code and starts conservatively translating the application.