Unisys Corporation

William E Oldham

Edward T Cavanagh

Douglas E Morrissey

Kin H Ng

Gene T Wieder

Michael John Bradley

Jason Shoemaker

James P Balcerek

Methods and apparatus for allocating access to a buffer of a host device to buffer data transferred between a controller of the host device and one or more remote devices are disclosed. The host device is configured to couple to each of the one or more remote devices through one or more corresponding dedicated lanes. Buffer access is allocated by determining, for each of one or more remote devices coupled to the host device, a number of dedicated lanes between the host device and each of the one or more remote devices and allocating access to the buffer of the host device for each of the one or more remote devices responsive to the determined number of dedicated lanes.

Methods and apparatus for allocating access to a host device buffer

Variable compensation for part to part skew of components in a substrate-mounted circuit is described. The variability may be provided through a computer software program acting on a programmable delay buffer such that compensation for a skewed signal may be continuously checked against a reference signal or through other methods. The skewed signal may be delayed until the signal matches, within a predetermined margin of error, the reference.

Systems and methods for overcoming part to part skew in a substrate-mounted circuit

Apparatus is provided for transferring user defined data from a parallel storage medium to a serial link driver in an I/O channel subsystem of a processor or I/O device controller. The serial link driver transmits a frame of user defined data over a serial data transfer medium. A data buffer receives and stores user defined data from the parallel storage medium. A control data facility that is distinct from the data buffer forms and transmits control data from the sender of the frame to the recipient of the frame via a path that does not include the data buffer. The control data facility includes respectively different dedicated logic for asynchronously generating each of the following: special character sequences, frame delimiters, headers, and cyclic redundancy checksums. A switching facility receives the user defined data from the data buffer. The switching facility also receives control data from the control data facility. The switching facility provides either the user defined data or the control data to the serial link driver. A data path control mechanism signals the switching facility to alternately provide the control data and the user defined data to the serial link driver, thereby forming frames.

Serial I/O channel having dependent and synchronous sources of control

An Input/Output (I/O) subsystem is provided for transferring frames containing frame control data from a serial data transfer medium to a parallel storage medium. The subsystem includes independent components for processing different portions of the received character stream. The subsystem includes a sequence recognition mechanism for receiving and identifying any of a plurality of digital data bit sequences. The sequences represent channel status information from the data transfer medium. The sequence recognition mechanism provides an interrupt signal derived from the sequences. A frame recognition mechanism responds to the interrupt signal. The frame recognition mechanism receives and identifies a start-of-frame delimiter or an end-of-frame delimiter from the data transfer medium. The frame recognition mechanism provides a frame status signal. A frame receiving mechanism responds to the frame status signal. The frame receiving mechanism receives and identifies a frame header from the data transfer medium. The frame receiving mechanism also verifies link and device level I/O protocol compliance asynchronously while any user defined data included in the frame are being received. The frame receiving mechanism also stores the user defined data in the parallel storage medium concurrently with the verification, if any user defined data are included.

Growing community of inventors

Pottstown, PA, United States of America

William E Oldham