Abstract: A method and apparatus for buffering data samples in a software-based ADSL modem. The method includes receiving samples of data in a buffer and determining if the received samples of data will exceed the storage capacity of the buffer. Selected samples of data from the buffer are deleted in response to the storage capacity being exceeded. The selected samples of data that were deleted are then reconstituted.

Abstract: A method and apparatus for buffering data samples in a software-based ADSL modem. The method includes generating data for transmission to a remote source and modulating the data to form a plurality of data symbols for transmission. The data symbols are stored in a buffer. An absence of a data symbol in the buffer is determined. In response to detecting an absence of a data symbol in the buffer, an idle data symbol is transmitted.

Abstract: A mechanism for minimizing interrupt context execution in a computer system by providing means for a driver to select the context for its execution. The operating system determines the system processing load and stores this information for use by the driver software. Based on the system processing load information, each driver then selects an execution context which meets its particular service requirements. When the system processing load is low and a lower-priority context will provide adequate service to the application, the lower-priority context is selected in order to reduce the amount of interrupt context execution. When the system processing load is high and a lower-priority context may not provide adequate service to the application, a higher-priority context is selected in order to ensure that execution of the application is within the driver's latency requirements.

Abstract: A modem to select a data transfer protocol based at least in part on conditions of the computing environment in which the modem is implemented. The modem includes means for monitoring the system processing load and selecting modem technologies and bit rates which are appropriate for current and anticipated system loading. The modem can determine system loading from measurements of microprocessor utilization in various execution contexts and can select a technology and bit rate which meets modem data transfer requirements while minimizing utilization during peak system loading.

Abstract: A modem which enables re-negotiation of the selected modem technology subsequent to the original negotiation which takes place at initiation of the modem connection. The invention includes means for one modem to interrupt data transfer and transmit a signal to the other modem indicating a request that a different modem technology be used. The request may be made as a result of changing line conditions, changing system demands, changing data transfer requirements, or other altered conditions under which the modems are operating. If the modem receiving the request accepts the request, both modems re-enter negotiation to select the best modem technology under the changed conditions. The modems are then re-trained to select the best bit rate within that technology under the existing line conditions. After the new modem technology and bit rate are selected, the modems resume transferring data.