Hewlett-Packard

About: Hewlett-Packard is a company organization based out in Palo Alto, California, United States. It is known for research contribution in the topics: Signal & Substrate (printing). The organization has 34663 authors who have published 59808 publications receiving 1467218 citations. The organization is also known as: Hewlett Packard & Hewlett-Packard Company.

Method and apparatus for supporting heterogeneous memory in computer systems

Abstract: A memory controller capable of supporting heterogeneous memory configurations enables seamless communications between a bus and memory modules having different characteristics. Thus, owners of computer systems need no longer replace entire memory arrays to take advantage of new memory modules; some memory modules may be upgraded to a new type while other memory modules of an older type remain. The memory controller receives memory requests from multiple processors and bus masters, identifies a memory module and memory access parameters for each request, accesses the memory and returns the resulting data (during a read request) or stores the data (during a write request). In some systems, the memory controller of the present invention is a two-tier memory controller system having a first memory controller coupled to the bus and to the second tier of memory controllers or RAM personality modules that translate between the first memory controller and a particular type of memory module. Typically, between the tiers a protocol is used which is representative of a typical clocked synchronous dynamic random access memory (SDRAM), although another protocol could be used. From the perspective of the processor bus or host bus coupled to the front end of the first memory controller, the entire memory controller system behaves as a single memory controller. From the perspective of memory, the back end of the RAM personality module is seen as a memory controller designed specifically to be configured for that memory type. Consequently, although the front end of the RAM personality module can be standardized across the system, compatible with the back end of the first memory controller, and in most embodiments of the present invention, the back end of the RAM personality module differs among the controller modules in the second tier, according to the variety of the memory modules in the memory system.

Apparatus controlled by data from consumable parts with incorporated memory devices

Abstract: A printing system includes a replaceable cartridge for housing a supply of consumable marking media. The cartridge includes a cartridge memory for recording printing system-related parameters, including marking media parameters. A replaceable printing device, such as an ink jet head, includes a printhead memory for recording printing device-related parameters. A processor is coupled to the cartridge memory, the printhead memory and is responsive to parameters read from both memories to derive printing system function control values that are dependent upon one or more marking media parameters from the cartridge memory and one or more parameters from the printhead memory. The processor is thus able (in the case of an ink jet printing system) to determine a current ink supply value from a cumulative usage value stored on the cartridge memory and a drop volume parameter stored on the printhead memory. Further, a drop volume parameter stored on the printhead memory can be adjusted to accommodate a media type sensed by a media sensor.

GEM: a generalized event monitoring language for distributed systems

Abstract: Event-based monitoring is critical for managing and debugging networks and distributed systems. This paper presents GEM - an interpreted generalized event monitoring language. It allows high-level, abstract events to be specified in terms of combinations of lower-level events from different nodes in a loosely coupled distributed system. Event monitoring components can thus be distributed within the system to perform filtering, correlation and notification of events close to where they occur and thus reduce network traffic. GEM is a declarative rule-based language in which the notion of real time has been closely integrated and various temporal constraints can be specified for event composition. The paper discusses the effect of communication delays on composite event detection and presents a tree-based solution for dealing with out-of-order event arrivals at event monitors.

An IC for linearizing RF power amplifiers using envelope elimination and restoration

Abstract: Efficient power amplifiers (PAs) are desirable because power amplifiers typically dominate the power consumed in portable radio devices. Cellular systems such as the advanced mobile phone system (AMPS) employ modulation schemes that generate constant amplitude RF outputs to use efficient but nonlinear PAs. Modern digital communication standards such as the North American dual-mode cellular (NADC) system require nonconstant amplitude RF outputs to maximize frequency spectral usage, and therefore require linear PAs. The traditional approach to linear RF power amplification is to back-off the output power of a PA until its distortion is reduced to an acceptable level. Power back-off can lead to significant reduction in output power and efficiency. The envelope elimination and restoration (EER) system is an alternative to power back-off, to simultaneously achieve efficiency and linearity in RF PAs.