Microsoft Technology Licensing, LLC

John Nels Fuller

Georgios Chrysanthakopoulos

Jameel Hyder

Kenneth Grey Richards

Mark R Sestak

Thomas W Green

A method and apparatus for directly creating a buffer of contiguous payload data from an incoming variable-length data stream utilizes a host controller for providing direct memory access (DMA) to a host computer memory. Payload data and header data from the data stream are stored contiguously in separate buffers in host memory. DMA descriptors, through appropriate software drivers, instruct the DMA engine of host controller to separate payload data and header data of each incoming packet on the data stream and place it in respective buffers in host memory. Thus, two separate logical buffers may be directly created from a single incoming logical variable-length data stream. Payload data is written directly and contiguously to host memory without the need for memory copies and the associated use of main processor resources.

Method and apparatus for direct buffering of a stream of variable-length data

Methods, systems, and computer program products for abstracting device driver development by layering certain functionality. A driver layer encapsulates device commands and data within a format that is independent of the type of connection between the device and a host computer. Once encapsulated, the device commands and data pass through an intermediate layer responsible for transferring the encapsulated device commands and data to a connection-specific layer. The connection-specific layer then places the encapsulated device commands and data on the particular connection that couples the device and host computer. A single driver layer, potentially provided by an operating system, can thus operate a plurality of devices. Accordingly, hardware developers can be freed from the burden of writing the numerous host-based device drivers that are otherwise required to support an increasing number of connections between devices and host computers, specifically exemplified by improved bus and networking technologies.

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John Nels Fuller