Abstract: Embodiments of a method for determining locations of computers in a group of computers, which may be performed by a system, are described. During operation, the system receives a location of a first computer in the group of computers. Then, the system determines locations of one or more additional computers in the group of computers relative to the first computer based on vibration spectra associated with the first computer and the one or more additional computers.

Abstract: Some embodiments of the present invention provide a system that characterizes a computer system parameter by analyzing a target electromagnetic signal radiating from the computer system. First, the target electromagnetic signal is monitored using a conductor in an interface of the computer system. Then, the target electromagnetic signal is analyzed to characterize the computer system parameter.

Abstract: Some embodiments of the present invention provide a system that estimates an ambient temperature of air outside of a computer system. During operation, a temperature inside the computer system is measured for different flow rates of air into the computer system. Next, the temperature measurements are used to determine a relationship between the temperature inside the computer system and a parameter related to the flow rate of air into the computer system. Then, the ambient temperature of air outside the computer system is estimated based on the relationship.

Abstract: Some embodiments of the present invention provide a system that includes a drive carrier for a hard disk drive (HDD) and one or more vibration control clips affixed to the drive carrier. Within this system, a mode of vibration of the HDD is modulated by contact between each of the vibration control clips and a surface within the computer system.

Abstract: Embodiments of a mechanical device to facilitate in-situ measurements of vibration associated with a corresponding component in a computer system are described. This mechanical device includes a housing that has approximately a same mass as the component, approximately a same distribution of mass about a geometric center of the component, and approximately a same form factor as the component. Moreover, the mechanical device includes one or more vibration sensors, which are mechanically coupled to the housing, and which are configured to perform the in-situ vibration measurements.

Abstract: Some embodiments of the present invention provide a system that schedules read operations for disk drives in a set of disk drives. During operation, the system monitors a write rate for write operations to a given disk drive in the set of disk drives, wherein vibrations generated by the read operations directed to disk drives in the set of disk drives are transmitted to the given disk drive. Then, the read operations for disk drives in the set of disk drives are scheduled based on the write rate for the given disk drive, thereby limiting interference between the write operations and the vibrations generated by the read operations.

Abstract: The air flow optimization apparatus includes a first member configured to attach to openings of an air vent on a server enclosure, such that the attachment of the first member to the air vent prevents air leakage. Further, the air flow optimization apparatus includes a second member configured to mount on top of a fan module connector within the server enclosure. A method for installing the air flow optimization apparatus includes inserting the first member into the openings of the air vent in a server enclosure, such that the first member includes attaching fins configured to be inserted into outer ends of the openings of the air vent. Further, the method for installing the air flow optimization apparatus also includes mounting the second member on top of a fan module connector, such that the second member includes engaging portions configured to engage with the fan module connector.

Abstract: A computer system uses transient blocking synchronization for performing operations on shared memory. When performing operations on more than one memory location, the computer system obtains transient exclusive access to a first memory location. The computer system then obtains transient exclusive access to a second memory location, where the transient exclusive access to the second memory location does not expire prior to an expiration of the transient exclusive access to the first memory location or until explicitly unleased.

Abstract: One embodiment of the present invention provides a system that prevents loops from occurring when spanning tree configuration messages are lost while executing a spanning tree protocol on bridges in a network. During operation, the system executes the spanning tree protocol on a bridge. This spanning tree protocol configures each port coupled to the bridge into either a forwarding state, in which messages are forwarded to and from the port, or a backup state, in which messages are not forwarded to or from the port. The system also monitors ports coupled to the bridge to determine when messages are lost by the ports. If one or more messages are lost on a port, the system refrains from forwarding messages to or from the port until no messages are lost by the port for an amount of time.

Abstract: A system that characterizes degradation of a component in a system. During operation, the system monitors inferential variables associated with a specimen of the component. Next, the system determines a time for the onset of degradation for the specimen and determines a time for the completion of degradation for the specimen. The system then computes a time interval between the onset of degradation and the completion of degradation, and uses the time interval to look up an entry in a defect library to obtain information which characterizes the degradation of the specimen of the component.

Abstract: Method and apparatus for transmitting messages between communication devices via a communication channel allowing at least voice messages to be transmitted, the messages including data subdivided in a sequence of basic data units, the method including: a) encoding the basic data units as unique signals (usj) including a predetermined number of basic signals (bi), each basic signal having a unique fixed frequency (fi); b) transmitting a sequence of unique signals (usj) during a sequence of fixed time periods (t1, t2, t3, . . . ); c) receiving and decoding the sequence of unique signals (usj) into the sequence of basic data units; the data being transmitted in superposition over voice.

Abstract: A telematics system is provided. The system includes a telematics client framework having an interface to client applications and being integrated with a client communications framework. The client communications framework has a client stream manager, a client data pump, a client policy manager, and a client channel monitor. The channel monitor detects availability of channels for communication with a telematics server framework. The telematics server framework includes an interface to server applications and is integrated with a server communications framework. The client channel monitor is configured to communicate availability of channels to connection objects of the client data pump. Switching between channels is triggered based on information obtained from the client policy manager.

Abstract: Advertising displays such as found in mass transit vehicles or stations or in electronic newspapers are provided with user directed search capabilities. Selected text, dragged and dropped onto an image space, serves to initiate a query. If the advertising display is networked, an external search of network resources, such as those of the World Wide Web, can be undertaken and the results utilized to initiate one or more local searches.

Abstract: A clock interpolation circuit for setting and controlling a phase of an output clock that is derived from an interpolation of multiple input clocks. Interpolation is performed by capacitively weighting the multiple clocks. A select and control circuit provides the ability to select different capacitance values to control the weighting. An optional buffer stage is also provided to sharpen the edge transitions of the interpolated clock.

Abstract: The problem of searching for a low cost path from a source location to a target location through a traversable region partitioned into a plurality of tiles is solved using source and target cost functions. Each tile in the traversable region is defined by boundary segments. The source cost function provides a cost for traversing from the source location to the boundary segment in question. The target cost function provides a cost for traversing from the boundary segment in question to the target location. The target cost function is estimated, and the source cost function is calculated. A path cost function is determined by adding the source and target cost functions. If the target location is a tile, then the target cost may be estimated using a convex hull of the target tile and the boundary segment in question. To facilitate the cost function calculations, multiple forms of cost function propagation between segments are disclosed.

Abstract: In a distributed computing system, a first process may register interest in an event occurring in another address space or physical machine in such a way as to allow the subsequent notification of the event's occurrence to contain an object that includes methods that are to be run on receipt of the notification. When the notification is received, either by the first process or by some other entity designated by the first process to be the final point of notification, the methods may be executed as specified by the first process.

Abstract: A method and apparatus for fast and reliable fencing of resources such as shared disks on a networked system. For each new configuration of nodes and resources on the system, a membership program module generates a new membership list and, based upon that, a new epoch number uniquely identifying the membership correlated with the time that it exists. A control key based upon the epoch number is generated, and is stored at each resource controller and node on the system. If a node is identified as failed, it is removed from the membership list, and a new epoch number and control key are generated. When a node sends an access request to a resource, the resource controller compares its locally stored control key with the control key stored at the node (which is transmitted with the access request). The access request is executed only if the two keys match.

Abstract: A method and apparatus is provided for enabling blocked remote methods to relinquish threads and other resources to other methods on a server system. In a distributed computing environment, remote methods are allocated numerous network resources but are blocked while they wait for operations, such as a write operation from another process, to complete. When enough remote methods are blocked, threads and other network resources may run out. Client systems requesting server services may experience slower response times. This method and system provides a technique for remote methods to relinquish network resources, such as threads, for other methods to use while the methods are blocked. Once the conditions causing the remote methods to block is resolved, the remote methods continue execution. This technique enables high volume client-server transaction systems to utilize threads and other resources in a distributed computing environment more efficiently.

Abstract: An improved lookup service is provided that allows for the dynamic addition and deletion of services. This lookup service allows for the addition and deletion of services automatically, without user intervention. As a result, clients of the lookup service may continue using the lookup service and its associated services while the updates occur. Additionally, the lookup service provides a notification mechanism that can be used by clients to receive a notification when the lookup service is updated. By receiving such a notification, clients can avoid attempting to access a service that is no longer available and can make use of new services as soon as they are added to the lookup service.

Abstract: A system for converting between parallel data and serial data is described. In the system 10, individual bits of the parallel data 12 are latched into individual registers 117. Each register 117 is coupled to a corresponding AND gate 110 which is also connected to receive phased clock signals. The output terminals of the AND gates 110 are connected to an OR gate 115. Using the system, with appropriately phased clocks, the parallel data is converted into serial data.