Abstract: Methods, systems, and apparatus for determining whether an access bit is set for each page table entry of a page table based on a scan of the page table with at least one page table walker, the access bit indicating whether a page associated with the page table entry was accessed in a last scan period; incrementing a count for each page in response to determining that the access bit is set for the page table entry associated with the page; resetting the access bit after determining whether the access bit is set for each page table entry; receiving a request to access, from a main memory, a first page of data; initiating a page fault based on determining that the first page of data is not stored in the main memory; and servicing the page fault with a DMA engine.

Abstract: Methods, systems, and apparatus for receiving a request to access, from a main memory, data contained in a first portion of a first page of data, the first page of data having a first page size; initiating a page fault based on determining that the first page of data is not stored in the main memory; allocating a portion of the main memory equivalent to the first page size; transferring the first portion of the first page of data from the secondary memory to the allocated portion of the main memory without transferring the entire first page of data; and updating a first page table entry associated with the first portion of the first page of data to point to a location of the allocated portion of the main memory to which the first portion of the first page of data is transferred.

Abstract: Methods, systems, and apparatus for determining whether an access bit is set for each page table entry of a page table based on a scan of the page table with at least one page table walker, the access bit indicating whether a page associated with the page table entry was accessed in a last scan period; incrementing a count for each page in response to determining that the access bit is set for the page table entry associated with the page; resetting the access bit after determining whether the access bit is set for each page table entry; receiving a request to access, from a main memory, a first page of data; initiating a page fault based on determining that the first page of data is not stored in the main memory; and servicing the page fault with a DMA engine.

Abstract: Methods, systems, and apparatus for receiving a request to access, from a main memory, data contained in a first portion of a first page of data, the first page of data having a first page size; initiating a page fault based on determining that the first page of data is not stored in the main memory; allocating a portion of the main memory equivalent to the first page size; transferring the first portion of the first page of data from the secondary memory to the allocated portion of the main memory without transferring the entire first page of data; and updating a first page table entry associated with the first portion of the first page of data to point to a location of the allocated portion of the main memory to which the first portion of the first page of data is transferred.

Abstract: Methods, systems, and apparatus for determining whether an access bit is set for each page table entry of a page table based on a scan of the page table with at least one page table walker, the access bit indicating whether a page associated with the page table entry was accessed in a last scan period; incrementing a count for each page in response to determining that the access bit is set for the page table entry associated with the page; resetting the access bit after determining whether the access bit is set for each page table entry; receiving a request to access, from a main memory, a first page of data; initiating a page fault based on determining that the first page of data is not stored in the main memory; and servicing the page fault with a DMA engine.

Abstract: Methods, systems, and apparatus for receiving a request to access, from a main memory, data contained in a first portion of a first page of data, the first page of data having a first page size; initiating a page fault based on determining that the first page of data is not stored in the main memory; allocating a portion of the main memory equivalent to the first page size; transferring the first portion of the first page of data from the secondary memory to the allocated portion of the main memory without transferring the entire first page of data; and updating a first page table entry associated with the first portion of the first page of data to point to a location of the allocated portion of the main memory to which the first portion of the first page of data is transferred.

Abstract: This disclosure provides systems, methods, and apparatus for mitigating the effects of interference signals on optical signals received at a direct-detection optical receivers. The optical receivers are capable of attenuating interference noise signals resulting from the interference between a transmitted optical signal transmitted from a transmitter to the optical receiver and one or more additional signals received at the optical receiver. The interference can be due to multi-path interference or due to in-band interference. The receivers include a tunable filter for filtering the received optical signal to remove the interference. A frequency offset module processes the received optical signal to determine a frequency offset indicative of the difference between the carrier frequencies of a modulated optical signal and an interference optical signal.

Abstract: Methods, systems, and apparatus for receiving a request to access, from a main memory, a first cache line of a page of data; determining that the first cache line is not stored in the main memory and is stored in a secondary memory, and in response: transferring the first cache line of the page of data from the secondary memory to the main memory without transferring the entire page of data, wherein a remaining portion of the page of data remains stored in the secondary memory; updating a page table entry associated with the page of data to point to a location of the page of data in the main memory; and transferring the remaining portion of the page of data from the secondary memory to the main memory.

Abstract: This disclosure provides systems, methods, and apparatus for mitigating the effects of interference signals on optical signals received at a direct-detection optical receivers. The optical receivers are capable of attenuating interference noise signals resulting from the interference between a transmitted optical signal transmitted from a transmitter to the optical receiver and one or more additional signals received at the optical receiver. The interference can be due to multi-path interference or due to in-band interference. The receivers include a tunable filter for filtering the received optical signal to remove the interference. A frequency offset module processes the received optical signal to determine a frequency offset indicative of the difference between the carrier frequencies of a modulated optical signal and an interference optical signal.

Abstract: This disclosure provides systems, methods, and apparatus for mitigating the effects of interference signals on optical signals received at a direct-detection optical receivers. The optical receivers are capable of attenuating interference noise signals resulting from the interference between a transmitted optical signal transmitted from a transmitter to the optical receiver and one or more additional signals received at the optical receiver. The interference can be due to multi-path interference or due to in-band interference. The receivers include a tunable filter for filtering the received optical signal to remove the interference. A frequency offset module processes the received optical signal to determine a frequency offset indicative of the difference between the carrier frequencies of a modulated optical signal and an interference optical signal.

Abstract: Methods, systems, and apparatus for receiving a request to access, from a main memory, data contained in a first portion of a first page of data, the first page of data having a first page size; initiating a page fault based on determining that the first page of data is not stored in the main memory; allocating a portion of the main memory equivalent to the first page size; transferring the first portion of the first page of data from the secondary memory to the allocated portion of the main memory without transferring the entire first page of data; and updating a first page table entry associated with the first portion of the first page of data to point to a location of the allocated portion of the main memory to which the first portion of the first page of data is transferred.

Abstract: Methods, systems, and apparatus for determining whether an access bit is set for each page table entry of a page table based on a scan of the page table with at least one page table walker, the access bit indicating whether a page associated with the page table entry was accessed in a last scan period; incrementing a count for each page in response to determining that the access bit is set for the page table entry associated with the page; resetting the access bit after determining whether the access bit is set for each page table entry; receiving a request to access, from a main memory, a first page of data; initiating a page fault based on determining that the first page of data is not stored in the main memory; and servicing the page fault with a DMA engine.

Abstract: Methods, systems, and apparatus for receiving a request to access, from a main memory, a first cache line of a page of data; determining that the first cache line is not stored in the main memory and is stored in a secondary memory, and in response: transferring the first cache line of the page of data from the secondary memory to the main memory without transferring the entire page of data, wherein a remaining portion of the page of data remains stored in the secondary memory; updating a page table entry associated with the page of data to point to a location of the page of data in the main memory; and transferring the remaining portion of the page of data from the secondary memory to the main memory.

Abstract: This disclosure provides systems, methods, and apparatus for mitigating the effects of interference signals on optical signals received at a direct-detection optical receivers. The optical receivers are capable of attenuating interference noise signals resulting from the interference between a transmitted optical signal transmitted from a transmitter to the optical receiver and one or more additional signals received at the optical receiver. The interference can be due to multi-path interference or due to in-band interference. The receivers include a tunable filter for filtering the received optical signal to remove the interference. A frequency offset module processes the received optical signal to determine a frequency offset indicative of the difference between the carrier frequencies of a modulated optical signal and an interference optical signal.

Abstract: This disclosure provides systems, methods, and apparatus for mitigating the effects of an optical link in a communication system on polarization angles of signals transmitted over the optical link. The communication system can include an optical transmitter transmitting polarization-division multiplexed (PDM) optical signals over the optical link and a direct-detection receiver for receiving the PDM optical signals. The transmitter can include a polarization compensation unit for receiving estimated values of link polarization parameters from the receiver. The receiver uses the estimated values to pre-distort modulator drive and bias signals and to adjust the relative phase between modulated optical signals. The transmitter can also transmit training optical signals to the receiver over the optical link. The receiver uses the training optical signals to estimate the values of link polarization parameters.

Abstract: Systems and methods for increasing bandwidth in a computer network are provided. A computer network can include a first lower level switch, first and second upper level switches, and first and second passive optical splitters, and a mirror. The first passive optical splitter can have a first port directly coupled to the first upper level switch, a second port directly coupled to the second upper level switch. The second passive optical splitter can have a port directly coupled to a port of the first passive optical splitter, and a port directly coupled to the first lower level switch. The mirror can be coupled to a port of the second passive optical splitter and reflect an optical signal received from the second passive optical splitter to the first upper level switch and second upper level switch through the second passive optical splitter and the first passive optical splitter.

Abstract: Systems and methods for increasing bandwidth in a computer network are provided. A computer network can include a first lower level switch, first and second upper level switches, and first and second passive optical splitters, and a mirror. The first passive optical splitter can have a first port directly coupled to the first upper level switch, a second port directly coupled to the second upper level switch. The second passive optical splitter can have a port directly coupled to a port of the first passive optical splitter, and a port directly coupled to the first lower level switch. The mirror can be coupled to a port of the second passive optical splitter and reflect an optical signal received from the second passive optical splitter to the first upper level switch and second upper level switch through the second passive optical splitter and the first passive optical splitter.

Abstract: Systems and methods for increasing bandwidth in a computer network are provided. A computer network can include a first lower level switch having a first port and a second port. The computer network can include a second lower level switch having a first port and a second port. The computer network can include an upper level switch having respective ports directly coupled to ports of the first and second lower level switches. A third port of the upper level switch can couple to a first port of a passive optical splitter. The passive optical splitter can have second and third ports coupled to respective ports of the first and second lower level switches. The passive optical splitter can be configured to transmit signals received at its first port as output signals on both of its second and third ports.

Abstract: Systems and methods for increasing bandwidth in a computer network are provided. A computer network can include a first lower level switch having a first port and a second port. The computer network can include a second lower level switch having a first port and a second port. The computer network can include an upper level switch having respective ports directly coupled to ports of the first and second lower level switches. A third port of the upper level switch can couple to a first port of a passive optical splitter. The passive optical splitter can have second and third ports coupled to respective ports of the first and second lower level switches. The passive optical splitter can be configured to transmit signals received at its first port as output signals on both of its second and third ports.

Abstract: A prosthetic foot assembly includes an ankle member, a heel member pivotally connected to the ankle member, an elongate metatarsal-toe member having a rear portion underlying a forward portion of the heel member and projecting forwardly from the heel member. The metatarsal-toe member is pivotally connected to the heel member. A first compressible element is engaged between a portion of the ankle member and a portion of the heel member and a second compressible element having first and second substantially circular bearing surfaces engaged between a portion of the heel member and a portion of the metatarsal-toe member to resist upward pivotal movement of a forward end of the metatarsal-toe member relative to the heel member. A portion of the compressible element spaced apart from one of the bearing surfaces has a smaller diameter than the diameter of at least one of the first and second bearing surfaces.