Abstract: Wearable spectroscopy systems and methods for identifying one or more characteristics of a target object are described. Spectroscopy systems may include a light source configured to emit light in an irradiated field of view and an electromagnetic radiation detector configured to receive reflected light from a target object irradiated by the light source. One or more processors of the systems may identify a characteristic of the target object based on a determined level of light absorption by the target object. Some systems and methods may include one or more corrections for scattered and/or ambient light such as applying an ambient light correction, passing the reflected light through an anti-scatter grid, or using a time-dependent variation in the emitted light.

Abstract: An optoelectronic apparatus includes a heat sink, which is shaped to define a base, a first platform at a first elevation above the base, and a second platform alongside the first platform at a second elevation above the base, which is different from the first elevation. A first monolithic emitter array is mounted on the first platform and is configured to emit first optical beams. A second monolithic emitter array is mounted on the second platform and is configured to emit second optical beams. An optical element is configured to direct both the first and the second optical beams toward a target region.

Abstract: A method and system for managing direct memory access (DMA) in a computer system without a host input/output memory management unit (IOMMU). The computer system hosts virtual machines and allows memory overcommit. The computer receives, from a guest operating system that runs on a virtual machine, a request for mapping a guest address to a bus address. The computer translates the guest address to a host address and pins a memory page containing the host address to keep the memory page in host memory. The host address is then returned to the guest operating system to allow a device to use the host address as the bus address for direct memory access (DMA) to a buffer managed by the guest operating system.

Abstract: A system and method for memory sharing among computer programs is disclosed. A method for memory sharing among computer programs includes identifying memory units of a plurality of memory units having identical contents, collapsing the identified memory units into a single merged memory page, and mapping the single merged memory page into an associated shared physical memory location. The method further includes when a request to write to a memory unit merged into the single merged memory page is received: copying, by a computer system, contents in the associated shared physical memory location to a different memory location, and redirecting, by the computer system, the request to the different memory location.

Abstract: A method and system for managing direct memory access (DMA) in a computer system that hosts virtual machines and allows memory overcommit. The computer receives an indication that a bus address is to be used by a device to perform DMA to a buffer. In response to the indication, the computer determines a host device identifier for the device, and pins a memory page addressed by a host address that is associated with the bus address and a guest address. The computer also records, in a host I/O memory management unit (IOMMU), a mapping of the bus address and the host device identifier to the host address. After the device completes the DMA, the computer removes the mapping from the host IOMMU to prevent further direct access to the host address.

Abstract: A system and method for memory sharing among computer programs is disclosed. A method for memory sharing among computer programs includes identifying memory units of a plurality of memory units having identical contents, collapsing the identified memory units into a single merged memory page, and mapping the single merged memory page into an associated shared physical memory location. The method further includes when a request to write to a memory unit merged into the single merged memory page is received: copying, by a computer system, contents in the associated shared physical memory location to a different memory location, and redirecting, by the computer system, the request to the different memory location.

Abstract: A physical memory location among multiple programs is shared among multiple programs. In one embodiment, multiple memory units are scanned to detect duplicated contents in the memory units. The memory units are used by programs running on a computer system. A data structure is used to identify memory units of identical contents. To improve performance, an additional data structure can be used to identify memory units of identical contents. Memory units that are identified to have identical contents can share the same physical memory space.

Abstract: A method and system for managing direct memory access (DMA) in a computer system without a host input/output memory management unit (IOMMU). The computer system hosts virtual machines and allows memory overcommit. The computer receives, from a guest operating system that runs on a virtual machine, a request for mapping a guest address to a bus address. The computer translates the guest address to a host address and pins a memory page containing the host address to keep the memory page in host memory. The host address is then returned to the guest operating system to allow a device to use the host address as the bus address for direct memory access (DMA) to a buffer managed by the guest operating system.

Abstract: A method and system for managing direct memory access (DMA) in a computer system that hosts virtual machines and allows memory overcommit. The computer receives an indication that a bus address is to be used by a device to perform DMA to a buffer. In response to the indication, the computer determines a host device identifier for the device, and pins a memory page addressed by a host address that is associated with the bus address and a guest address. The computer also records, in a host I/O memory management unit (IOMMU), a mapping of the bus address and the host device identifier to the host address. After the device completes the DMA, the computer removes the mapping from the host IOMMU to prevent further direct access to the host address.

Abstract: A physical memory location among multiple programs is shared among multiple programs. In one embodiment, multiple memory units are scanned to detect duplicated contents in the memory units. The memory units are used by programs running on a computer system. A data structure is used to identify memory units of identical contents. To improve performance, an additional data structure can be used to identify memory units of identical contents. Memory units that are identified to have identical contents can share the same physical memory space.