Abstract: The present invention discloses an apparatus and method for maintaining the coherence of data within a shared memory network including a plurality of nodes. The system utilizes processors monitoring the occurrence of particular processing events within a local memory storage area. Upon the detection of events indicating the change of status of a particular group of data, a comparison is made between a modified copy of the group of data and a clean copy of the group of data to detect any modifications made to the group of data. These modifications are entered into the clean copy of the group of data and processing continues.
Type:
Grant
Filed:
March 26, 1998
Date of Patent:
January 22, 2002
Assignee:
Compaq Computer Corporation
Inventors:
Leonidas Kontothanassis, Michael L. Scott, Robert Stets, Sandhya Dwarkadas, Nikos Hardavellas, Galen Hunt
Abstract: An encoded loss resilient message, includes a first number of first data items, a second number of second data items, and a third number of third data items. Respective portions of the first data items correspond to different numbers of associated second data items in a first distribution. Respective portions of the second data items correspond to different numbers of associated first data items in a second distribution. Respective portions of the second data items correspond to different numbers of associated third data items in a third distribution which is proportional to the first distribution with the different numbers of associated third data items equaling the different numbers of associated second data items multiplied by the first number divided by the second number.
Type:
Grant
Filed:
November 6, 1997
Date of Patent:
February 27, 2001
Assignee:
Compaq Computer Corporation
Inventors:
Michael G. Luby, Michael D. Mitzenmacher
Abstract: A method of reconstructing an image from a dithered image. A predefined set of filters having different regions of support is established. Each filter is defined by a number of filter coefficients and an impulse response function which defines the filter response for a region of support outside of which the impulse response is zero. Filters are organized according to indexes and this organization represents the order in which the filters are considered during a filter selection process. The filter selection process selects a filter constrained by the rule that the filter selected must only perform low-pass filtering on a region of support that does not contain edges of an image. Due to the organization of the filter set, the filter selection process first selects the largest filter from the filter set that fits within the region about the current processed pixel. If there is an edge of an image within the support region of the first selected filter, the next smaller filter is selected.
Type:
Grant
Filed:
January 30, 1998
Date of Patent:
February 6, 2001
Assignee:
Compaq Computer Corporation
Inventors:
Shiufun Cheung, Robert A. Ulichney, Robert MacNamara, Giridharan Iyengar