Abstract: One embodiment of the present invention provides a method for calibrating a rotary encoder including a rotatable disk including at least two index points located along a circumferentially extending row. These index points contain information specifying an angular position of the index point. This allows the rotary encoder to be calibrated by turning it through a sufficient angular displacement to ensure that an index point passes over a sensor. This sufficient angular displacement is less than a complete revolution because there are multiple index points along the circumference of the disk. This design allows a rotary encoder to be calibrated without turning it through a complete revolution. This is advantageous where turning the rotary encoder through a complete rotation is not possible or is inconvenient, for example in applications such as a wind direction indicator, a rudder position indicator or a joystick.

Abstract: One embodiment of the present invention provides a method for designing a circuit that limits the impact of design changes within a module of a circuit to the characteristics of signals flowing between modules of the circuit. This method operates by dividing the circuit into a plurality of circuit modules, and defining a plurality of interface modules located between the plurality of circuit modules. These interface modules include drivers coupled between upstream circuit module outputs and downstream circuit module inputs, so as to isolate the downstream circuit module inputs from the upstream circuit module outputs. Next, the circuit modules and interface modules are designed, and a synthesized circuit is ultimately generated from the designs. This synthesized circuit is then verified for characteristics such as timing. If it fails to verify, design changes are made.

Abstract: One embodiment of the present invention provides a method and an apparatus that ensures proper semantics for operations when operations are restarted on a secondary server in the event of a failure of a primary server. This embodiment keeps a record on the secondary server of which operation currently has exclusive access to a shared resource. The method operates by receiving a message from the primary server indicating that a first operation on the primary server has acquired exclusive access to the shared resource. In response to this message, the system updates state information, at the secondary server, to indicate that the first operation has exclusive access to the shared resource and that any prior operations have completed their exclusive accesses to the shared resource. Upon receiving notification that the primary server has failed, the secondary server is configured to act as a new primary server.

Abstract: One embodiment of the present invention provides an apparatus for removing signals and power from a bus card in a computer system when the bus card is inadvertently removed from the computer system while the computer system is operating. This apparatus includes a bus connector, for receiving a bus card, and a power conductor to provide an electrical coupling between the bus card and a power source. The apparatus also includes a power switch coupled between the power conductor and the bus connector, to selectively provide power to a bus card in the bus connector. The apparatus additionally includes a movement sensor, for sensing a movement of the bus card from the bus connector. The apparatus also includes a controller coupled between the movement sensor and the power switch, for activating the power switch to remove power from the bus card when the movement sensor detects a movement of the bus card from the bus connector.

Abstract: The present invention provides a method and an apparatus for providing a first computer program module with the ability to access a service from a second computer program module. The method includes receiving the first computer program module--for example, at a third party computer system, and determining whether the first computer program module has been digitally signed by an authority having power to confer access for the service. If so, the method provides the first computer program module with access to the service. A variation on this embodiment includes verifying that the first computer program module includes a chain of certificates establishing a chain of authorization for the service.

Abstract: One embodiment of the present invention provides a method and an apparatus for providing a client-side intermediary that communicates with an application on a second server computer system. The method operates by receiving a composite message at a client computer system from a first server computer system, and examining type information from the composite message. This type information specifies how the composite message is formatted, and can be used to select an application that is capable of processing the composite message. The method uses the type information to look up a network address of the application residing on the second server computer system. This address is used to forward the composite message to the application on the second server computer system. The above embodiment can be implemented within a browser on the client computer system, or within a separate application on the client computer system.

Abstract: An apparatus for firmware authentication and methods of operating the same result in software upgradability to firmware without compromising the integrity of the firmware. The apparatus for firmware authentication of a boot PROM comprises a software programmable data section having a plurality of micro-code. An authentication section having a hash generator configured to generate a data hash in response to the plurality of micro-code programmed in the software programmable data section to authorize execution of the plurality of micro-code of the data section.

Abstract: One embodiment of the present invention provides a system for predicting an address of an instruction following a branch instruction in a computer instruction stream. This system concurrently performs a fast single-cycle branch prediction operation to produce a first predicted address, and a more-accurate multiple-cycle branch prediction operation to produce a second predicted address. The system assumes that the first predicted address is correct and proceeds with a subsequent instruction fetch operation using the first predicted address. If the first predicted address is the same as the second predicted address, the subsequent instruction fetch operation is allowed to proceed using the first predicted address. Otherwise, the subsequent fetch operation is delayed so that it can proceed using the second predicted address.

Abstract: One embodiment of the present invention provides a method and an apparatus for controlling access to services in a protected memory system. The method makes use of a permit, which includes an access control mechanism that resides in a memory space that is protected from a user of the permit. The method includes receiving a request for a service through a permit, the permit comprising an object defined within an object-oriented programming system. In response to the request, the method activates an access control mechanism within the permit. This access control mechanism controls access to the service and resides in a memory space that is protected from a user of the permit, such that the access control mechanism is triggered by invoking a method on the permit. If the access is allowed, the method accesses the service by performing an invocation on a controlled object. This controlled object includes methods to perform the service, and is otherwise protected from the user of the permit.

Abstract: One embodiment of the present invention provides a method for constructing a query for an object-relational database. This method displays at least part of a schema for the object-relational database to a user in a graphical representation. Next, the method allows the user to perform graphical manipulations on the schema. The method then generates a query based upon the schema and the graphical manipulations, and this query is sent to the object-relational database. Another embodiment of the present invention provides a method for processing an object-relational query for transmission from a client to an object-relational database server. This method receives the query at the client, and parses the query to determine which object-relational structures the query is attempting to access.

Abstract: Apparatus, methods, systems, and computer program products are disclosed that locate a modified pointer value in a carded heap memory. A plurality of nodes is allocated from the carded heap memory. The carded heap contains at least one structure that indicates the existence or non-existence of a node reference for each card. For those cards containing a node reference the structure also includes the offset from the start of the card to the node reference. A card index or pointer within a card (that is used to generate a card index) is given to the invention. The card index is used to specify a first card. A second card is found given the card index. The invention then follows, starting at the first node in the second card and using the node advance value for each followed node, the nodes in the carded memory area until it locates the node containing the pointer in the first card.

Abstract: One embodiment of the present invention provides a system for predicting an address of an instruction following a branch instruction in a computer instruction stream. This system receives a current address specifying an address of a current instruction. It uses this current address (or possibly a preceding address) to generate a first select signal, which is used to select a first predicted address of an instruction following the current instruction in the computer instruction stream. At the same time the system generates a second select signal, which takes more time to generate than the first select signal but achieves a more accurate selection for a predicted address of the instruction following the current instruction. The system assumes that the first predicted address is correct and proceeds with a subsequent instruction fetch operation using the first predicted address. Next, the system compares the first select signal with the second select signal.

Abstract: One embodiment of the present invention provides a method for preparing a computer system for removal of a processor module from the computer system while the computer system is operating. This method includes receiving a command to prepare the computer system for removal of the processor module, and saving state from the processor module to a first location in the computer system. In response to this command, the method modifies parameters of an operating system in the computer system so that the computer system will continue to function without the processor module. The method also removes power from the processor module while maintaining power to other parts of the computer system. Thus, this embodiment of the present invention allows the processor module to removed, replaced and reinitialized without shutting down the computer system.

Abstract: One embodiment of the present invention provides a method for aligning a data signal and a data clock signal received from a memory during a read operation. The method includes receiving the data signal and the data clock signal from the memory, and determining an offset between these signals. If the offset is outside of a valid range, the system adjusts a delay between the data clock signal and the data signal. In a variation on the above embodiment, the method is performed by special-purpose hardware located in a memory controller, and operates periodically while the computer system is running. In another variation, the method is carried out by a BIOS program stored in read only memory, and operates during system startup.

Abstract: One embodiment of the present invention provides an apparatus for updating wallpaper for computer display including a server coupled to a network. The apparatus also includes a wallpaper database in communication with the server, for storing a collection of wallpapers for computer display, and a user database for storing personal profiles of system users. The apparatus employs a fetching mechanism within the server for retrieving the wallpaper from the wallpaper database based upon a personal profile of a user stored in the user database. This personal profile may specify an interest of the user and may also keep track of previous accesses of the user. In one embodiment, the server includes a website through which clients can navigate and access the wallpaper database. In a variation on this embodiment, the website includes a public portion, which is accessible to any registered user via the Internet, and a private portion, which is accessible only to users who are registered to access the private portion.

Abstract: One embodiment of the present invention provides an apparatus for aligning a data signal and a data clock signal received from a memory during a read operation. The apparatus includes a data input for receiving the data signal, and a clock input for receiving the data clock signal. The data signal and the data clock signal feed into an offset mechanism that determines an offset between the data clock signal and the data signal. This offset feeds into a comparison mechanism that determines if the offset is outside of a valid range. If the offset is outside of the valid range, an adjustment mechanism adjusts a delay between the data clock signal and the data signal. In a variation on the above embodiment, the apparatus is implemented in special-purpose hardware within a memory controller, and operates periodically while the computer system is running. In another variation, the apparatus is implemented as part of a system BIOS program stored in read only memory and operates during system startup.

Abstract: One embodiment of the present invention can be characterized as a method for designing a circuit that facilitates sharing of design parameters between separately designed modules of the circuit. The method includes receiving module information, including parameters relating to design of a module of the circuit, and storing the module information in a database. The method also includes retrieving the module information from the database, and generating automatically a constraint file from the module information. In one embodiment, this constraint file includes constraints in a format suitable for use by a synthesis tool to synthesize circuitry for the module.

Abstract: An efficient memory retrieval/storage schemes for a fault tolerant memory control system for a computer system having a host processor, a mass storage memory and a system interconnect. The memory control system includes a primary memory controller and a backup memory controller with taps between the memory controllers to increase fault tolerance. Data is transferred between the host processor and the mass storage memory in the form of data packets. During a write operation, instead of receiving a data packet from the host processor, storing the data content, retrieving the data and then generating a new data packet for the mass storage memory, the memory controller redirects the data packets without the need to copy the data into the controller cache.

Abstract: Apparatus, methods, systems and computer program products are disclosed that improve the efficiency of mutator programs and garbage collection programs that process objects containing null pointers in an object-oriented programming environment with statically typed variables. This improvement is achieved by allocating a NULL object within a controlled access memory area. Access to the NULL object is enabled when garbage collecting nodes and disabled while the mutator accesses the nodes.

Abstract: A trigger is provided in association with a network naming service, such as DNS (Domain Name Service), that handles client requests for an application. The trigger comprises a set of executable instructions referenced by a resource record associated with an identifier of the application. In response to a client request concerning the application, the resource record is retrieved and the instructions are executed. In one implementation of a trigger, a DNS server provides load balancing among a plurality of servers within a network name space (e.g., domain or sub-domain) offering an application program (or replicated service) that is known by a virtual server name. A policy is selected for choosing a preferred server from the plurality of servers according to a specified status or operational characteristic of the application instances, such as the least-loaded instance of the application or the instance with the fastest response time.