Xerox Corporation

Frederic J Stann

Juan A Romano

David Plakosh

Guillermo Lao

Mark A Smith

Michael A Wiegand

Michael C Lacagnina

Norman E Wright

Steven E Chen

Aram Nahidipour

In the UNIX Operating System, modifying the kernel routine Physio, to enable a single system call to set up a number of concurrent direct memory access (DMA) channels between memory and the data buffers of a device. Many character device drivers use the UNIX Physio facility for I/O. The traditional implementation of Physio handles I/O in a serial manner by performing gather-write or scatter-read operations. This invention is an enhancement to Physio to support parallel I/O operations.

Method of using the UNIX physio to allow data to be transferred on a

In a real-time printing system, in which large blocks of digital data corresponding to page images must be located in a memory via a translation table and accessed from the memory within a very narrow time frame, the memory-management internal program of an operating system is overridden by external instructions which lock the translation table in memory.

Real-time image data access from virtual memory in a digital printing

In a high-speed digital printing apparatus having duplex capability, second-side images must be rotated. In order to quickly rotate the second-side images, the image data for the images are read out from memory in a reverse order of addresses, with each address corresponding to one byte. As each byte is transferred to an imager, a relationship of sets of bits, each set of bits corresponding to one pixel, are altered within each byte.

Image rotation from virtual memory in a digital printing system

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Moorpark, CA, United States of America

Frederic J Stann