Abstract: An electrically conductive sidewall for an electromagnetic transducer having a magnetoresistive sensor is formed as a layer oriented substantially perpendicular to other layers of the sensor, and is used as a mask for defining the width of the sensor. This allows the sensor to be made much thinner than conventional sensors, providing higher resolution in a track width direction. The sidewall can be nonmagnetic, serving as a spacer between the magnetic sensor layers and an adjacent magnetic shield without the need for a protective cap to guard against damage from polishing and wet etching. Alternatively, the sidewall can be magnetic, serving as an extension of the shield. In either case, the sidewall reduces the effective length of the sensor for linear resolution, sharpening the focus of the sensor and increasing linear density. Also reduced is the tolerance for error in sensor width and length.

Abstract: A host CPU runs a network protocol processing stack that provides instructions not only to process network messages but also to allocate processing of certain network messages to a specialized network communication device, offloading some of the most time consuming protocol processing from the host CPU to the network communication device. By allocating common and time consuming network processes to the device, while retaining the ability to handle less time intensive and more varied processing on the host stack, the network communication device can be relatively simple and cost effective. The host CPU, operating according to instructions from the stack, and the network communication device together determine whether and to what extent a given message is processed by the host CPU or by the network communication device.

Abstract: At least one intelligent network interface card (INIC) is coupled to a host computer to offload protocol processing for multiple network connections, reducing the protocol processing of the host. Plural network connections can maintain, via plural INIC ports and a port aggregation switch, an aggregate connection with a network node, increasing bandwidth and reliability for that aggregate connection. Mechanisms are provided for managing this aggregate connection, including determining which port to employ for each individual network connection, and migrating control of an individual network connection from a first INIC to a second INIC.

Abstract: A system for protocol processing in a computer network has an intelligent network interface card (INIC) or communication processing device (CPD) associated with a host computer. The CPD provides a fast-path that avoids protocol processing for most large multipacket messages, greatly accelerating data communication. The CPD also assists the host CPU for those message packets that are chosen for processing by host software layers. A context for a message is defined that allows DMA controllers of the CPD to move data, free of headers, directly to or from a destination or source in the host. The context can be stored as a communication control block (CCB) that is controlled by either the CPD or by the host CPU. The CPD contains specialized hardware circuits that process media access control, network and transport layer headers of a packet received from the network, saving the host CPU from that processing for fast-path messages.

Abstract: A tunneling barrier for a spin dependent tunneling (SDT) device is disclosed that includes a plurality of ferromagnetic particles. The presence of such particles in the tunneling barrier has been found to increase a magnetoresistance or &Dgr;R/R response, improving the signal and the signal to noise ratio. Such an increased &Dgr;R/R response also offers the possibility of decreasing an area of the tunnel barrier layer and/or increasing a thickness of the tunnel barrier layer. Decreasing the area of the tunnel barrier layer can afford improvements in resolution of devices such as MR sensors and increased density of devices such as of MRAM cells. Increasing the thickness of the tunnel barrier can afford improvements in manufacturing such as increased yield.

Abstract: A network interface device provides a fast-path that avoids most host TCP and IP protocol processing for most messages. The host retains a fallback slow-path processing capability. In one embodiment, generation of a response to a TCP/IP packet received onto the network interface device is accelerated by determining the TCP and IP source and destination information from the incoming packet, retrieving an appropriate template header, using a finite state machine to fill in the TCP and IP fields in the template header without sequential TCP and IP protocol processing, combining the filled-in template header with a data payload to form a packet, and then outputting the packet from the network interface device by pushing a pointer to the packet onto a transmit queue. A transmit sequencer retrieves the pointer from the transmit queue and causes the corresponding packet to be output from the network interface device.

Abstract: An overcoat overcoat for a head and/or media surface is made of a hard, dense and durable silicon-carbide (SiC) layer. The SiC layer does not require an interlayer to promote adhesion to underlying magnetic or ceramic layers, thus reducing head-media spacing and increasing areal storage density and resolution. The SiC is formed in a manner that creates an overcoat with density, hardness, durability and corrosion resistance similar to DLC. The SiC overcoat formation process also penetrates less into underlying magnetic layers than is conventional, reducing further the spacing of active elements by inactive coatings. In an alternative embodiment, SiC may be formed by this process as an interlayer for a carbon overcoat such as DLC or ta-C. This allows the overcoat to be made thinner, since the interlayer is hard and dense, while retaining the chemical and other surface properties of the carbon overcoat.

Abstract: An apparatus that reduces sampling errors for data communicated between devices uses phase information acquired from a timing reference signal such as a strobe signal to align a data-sampling signal for sampling a data signal that was sent along with the timing reference signal. The data-sampling signal may be provided by adjustably delaying a clock signal according to the phase information acquired from the strobe signal. The data-sampling signal may also have an improved waveform compared to the timing reference signal, including a fifty percent duty cycle and sharp transitions. The phase information acquired from the timing reference signal may also be used for other purposes, such as aligning received data with a local clock domain, or transmitting data so that it arrives at a remote device in synchronism with a reference clock signal at the remote device.

Abstract: A magnetoresistive (MR) transducer has at least one insulative layer made of tetrahedral amorphous carbon (ta-C). The ta-C layer is formed by filtered cathodic arc deposition, has an essentially zero concentration of hydrogen and can serve as a read gap for the transducer. The hydrogen-free t-aC read gap has high thermal conductivity, keeping an adjoining MR sensor from overheating during operation. This extends sensor lifetimes and/or improves sensor performance. The read gap also has low defects and porosity, preventing unwanted electrical conduction or shorting between a sensor and a shield. The high hardness of the read gap resists plasma and chemical etching processes such as ion milling that are used to form the sensor. The increased hardness and reduced defects and porosity allow the read gaps to be made thinner without risking electrical shorting. Other hydrogen-free t-aC layers are employed for other sensor elements where electrical insulation and reduced thickness are important.

Abstract: A hard disk drive head operates in close proximity and dynamic contact with a rapidly spinning rigid disk surface, the head including a transducer with a magnetically permeable path between a poletip disposed adjacent to the disk surface and a magnetoresistive (MR) sensor situated outside the range of thermal noise generated by the surface contact. The magnetically permeable path is the same as that used to write data to the disk, eliminating errors that occur in conventional transducers having MR sensors at a separate location from the writing poletips. Moreover, the magnetically permeable path is preferably formed in a low profile, highly efficient “planar” loop that allows for manufacturing tolerances in throat height and wear of the terminal poletips from disk contact without poletip saturation or poletip smearing. The MR layer is formed in one of the first manufacturing steps atop the substrate, so that the MR layer has a relatively uniform planar template that is free from contaminants.

Abstract: A transducer for a hard disk drive system has a planar magnetic core and a pair of poletips that project transversely from the core for sliding contact with the disk during reading and writing. The transducer is formed entirely of thin films in the shape of a low profile table having three legs that slide on the disk, the poletips being exposed at a bottom of one of the legs for high resolution communication with the disk, the throat height of the poletips affording sufficient tolerance to allow for wear. The legs elevate the transducer from the disk sufficiently to minimize lifting by a thin air layer that moves with the spinning disk which, in combination with the small size of the thin film head allows a low load and a flexible beam and gimbal to hold the transducer to the disk.

Abstract: A device for queuing information combines the speed of SRAM with the low cost and low power consumption of DRAM, affording substantial expansion of high-speed data storage in queues without corresponding increases in costs. The queues have a variable size, and provide fast, flexible and efficient data storage via an SRAM interface and a DRAM body. The queues may hold pointers to buffer addresses or other data that allow manipulation of information in the buffers via manipulation of the queues. Particular utility for this mechanism exists in situations for which high-speed access to queues is beneficial, flexible queue size is advantageous, and/or the smaller size and lower cost of DRAM compared to SRAM is of value.

Abstract: A magnetic force microscope (MFM) needle has a magnetic material with a magnetic moment that is pinned in a preferred direction. The magnetic moment can be of lower than conventional magnitude without risking an undesirable change in the direction of magnetization. The magnetic needle can have a ferromagnetic layer (or layers) that is stabilized by an antiferromagnetic layer (or layers). The needle can be employed as a magnetoresistance sensitivity microscope (MSM) to map the sensitivity of a magnetic sensor, such as a magnetoresistive (MR) or giant magnetoresistive (GMR) sensor. Alternatively, the needle can be employed in measuring magnetic fields, such as with a high frequency magnetic force microscope (HFMFM).

Abstract: Plural carbon-containing overcoats are formed on a media-facing surface of an information storage system head. The plural carbon-containing overcoats can mitigate corrosion without increasing head-media spacing. A first of the overcoats may be formed prior to creation of contact or air bearing features on the media-facing surface, with a second overcoat formed after creation of air bearing features. The first overcoat may be etched back substantially or completely prior to formation of the second overcoat. Laminated carbon-containing overcoats may have greater strength and/or coverage than non-laminated overcoats of the same thickness. The overcoats may be formed of several forms of diamond-like carbon (DLC) or silicon-carbide (SiC).

Abstract: An intelligent network interface card (INIC) or communication processing device (CPD) works with a host computer for data communication. The device provides a fast-path that avoids protocol processing for most messages, greatly accelerating data transfer and offloading time-intensive processing tasks from the host CPU. The host retains a fallback processing capability for messages that do not fit fast-path criteria, with the device providing assistance such as validation even for slow-path messages, and messages being selected for either fast-path or slow-path processing. A context for a connection is defined that allows the device to move data, free of headers, directly to or from a destination or source in the host. The context can be passed back to the host for message processing by the host. The device contains specialized hardware circuits that are much faster at their specific tasks than a general purpose CPU.

Abstract: An intelligent network interface card (INIC) or communication processing device (CPD) works with a host computer for data communication. The device provides a fast-path that avoids protocol processing for most messages, greatly accelerating data transfer and offloading time-intensive processing tasks from the host CPU. The host retains a fallback processing capability for messages that do not fit fast-path criteria, with the device providing assistance such as validation even for slow-path messages, and messages being selected for either fast-path or slow-path processing. A context for a connection is defined that allows the device to move data, free of headers, directly to or from a destination or source in the host. The context can be passed back to the host for message processing by the host. The device contains specialized hardware circuits that are much faster at their specific tasks than a general purpose CPU.

Abstract: A host CPU runs a network protocol processing stack that provides instructions not only to process network messages but also to allocate processing of certain network messages to a specialized network communication device, offloading some of the most time consuming protocol processing from the host CPU to the network communication device. By allocating common and time consuming network processes to the device, while retaining the ability to handle less time intensive and more varied processing on the host stack, the network communication device can be relatively simple and cost effective. The host CPU, operating according to instructions from the stack, and the network communication device together determine whether and to what extent a given message is processed by the host CPU or by the network communication device.

Abstract: A disk drive system for contact recording has a flexure beam holding a transducer at one end, the flexure beam being oriented substantially along the direction that the transducer slides on a rigid magnetic disk. The transducer has a protrusion which contacts the disk and separates the rest of the transducer from the moving air film that adjoins the spinning disk, the protrusion containing a magnetic pole structure that communicates with the disk during sliding. A preferred embodiment employs a gimbal structure which allows limited movement of the transducer relative to the flexure beam and three disk-contacting pads extending down from the transducer to make contact with the magnetic disk, at least one of the pads containing a magnetic pole structure and two of the pads trailing the third pad.

Abstract: A magnetic head has an exchange isolated poletip located between a shield of an MR sensor and a write pole of an inductive sensor. The poletip is preferably made of high Bs material, allowing the flux that travels through the much larger pole layer to funnel through the poletip without saturation. The poletip is isolated from the shield layer in order to decouple the shield layer from unfavorable domain patterns that may occur in the poletip, which in turn reduces noise in the sensor, while the shield layer serves to complete the inductive circuit. Despite having a poletip isolated by nonmagnetic material, heads built according to this invention have demonstrated high overwrite as well as remarkably low noise.

Abstract: A system for protocol processing in a computer network has an intelligent network interface card (INIC) or communication processing device (CPD) associated with a host computer. The INIC provides a fast-path that avoids protocol processing for most large multi-packet messages, greatly accelerating data communication. The INIC also assists the host for those message packets that are chosen for processing by host software layers. A communication control block for a message is defined that allows DMA controllers of the INIC to move data, free of headers, directly to or from a destination or source in the host. The context is stored in the INIC as a communication control block (CCB) that can be passed back to the host for message processing by the host. The INIC contains specialized hardware circuits that are much faster at their specific tasks than a general purpose CPU.