Honeywell G.m.b.h.

Wave Technologies, Inc.

James F Hoff

Patrick S Gonia

Gary William Box

Dennis J Leisz

John A Perlick

Terry T Steeden

Rodney G Herreid

Curtis R Alexander

Thomas S Foote-Lennox

John J Turner

A high performance transport layer checksum calculation unit and method is described for use in computer data communications systems which provides simultaneous general purpose data movement and checksum calculations. Data must be copied from the main memory of a computer in order to be transmitted and often a checksum must be calculated on the data for error detection purposes. The invention involves performing both of these tasks simultaneously thus requiring only one scan of the data memory. The checksum calculation method improves throughput capacity via a unique hardware architecture supporting delayed checksumming of packet segments. A net improvement for packets larger than a certain size is achieved via partial addition during DMA controlled memory access allowing improved average cycle time per data packet segment.

Checksum calculation unit and method for error detection on data packets

The present invention relates to time measurement apparatus and method for measuring, with picosecond precision, intervals between single edged events, where each measured interval comprises the summation of a rough clock count and fine or calibrated vernier counts of measured fractional clock periods before and after each START and STOP event selected from a calibrated vernier memory. The calibrated vernier memory takes the form of a table of linear voltage versus time developed using pseudo-random generated measurement events of random duration and random separation.

Method and apparatus for asynchronous time measurement

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Shoreview, MN, United States of America

James F Hoff