Xerox Corporation

Randall J Stegbauer

Ronald A Ippolito

Kitty Sathi

Colleen R Enzien

Ernest L Legg

Anthony M Federico

Christopher Comparetta

Keith A May

Thomas M Frey

An electronic image processing apparatus comprising an electronic scanner and an electronic printer for forming an image, a controller for directing the operation of the image processing means, the controller including a mass memory device for storing data to be printed, random access memory, a printer control, and a Resource Manager for ensuring access to the random access memory for conveying data from the mass memory device to the printer via the random access memory, the Resource Manager including a mass memory device scheduler to provide printer access to the random access memory, the mass memory device scheduler having a reservation queue to reserve mass memory device access at predetermined times, delay means to determine that access to the mass memory device is invalid within a given time, and means to convey disk request operations to said reservation queue in order to provide guaranteed random access mernory at predetermined times.

Scheduling multiple disk requests and writing data buffers to disk

In accordance with the present invention there is provided a method for scheduling transfers in a printing machine of the type having a scheduler communicating with both a first disk and a second disk, the first and second disks having a combined bandwidth. The method for scheduling comprises the following steps: First, a first transfer to be performed on a first location of the first disk during a first time interval and a second transfer to be performed on a second location of the first disk during a second time interval are both scheduled, with the scheduler, so that a first time gap interval exists between the first time interval and the second time interval. Second, a third transfer to be performed on a first location of the second disk during a third time interval and a fourth transfer to be performed on a second location of the second disk during a fourth time interval are both scheduled, with the scheduler, so that a second time gap interval exists between the third time interval and the fourth time interval. Finally, a fifth transfer to be performed during a fifth interval is scheduled, with the scheduler, so that the fifth interval occurs during either the first time gap interval or the second time gap interval in a manner that maximizes the combined bandwidth of the first and second disks.

Dispatching and scheduling memory operations in an electronic printing

An electronic printing system with plural hard disks for storing system files in which critical system files are stored in duplicate at the same address on each disk, while non-critical files are divided into smaller segments with each file segment stored on a different one of the hard disks.

File storage process for electronic printing systems having multiple

An electronic image processing apparatus having image processing resources including a controller for directing the operation of the image processing resources, the controller including a disk memory, the method of controlling mass memory device bandwidth access during an access time window including guaranteeing access to the memory for predetermined time periods for a first set of image processing resources during each access time window, a second set of image processing resources having access subordinate to the first set of image processing resources, maintaining a record of mass memory device access for the first set of image processing resources during each access time window, receiving a memory access request from the first set of image processing resources, determining that said resource utilization does not exceed the predetermined time period, and allowing current access to the mass memory device by the image processing resource. The second set of image processing resources achieves access upon determination that none of the first set of resources is requesting access or upon determination that each of the first set of resources has exceeded the predetermined time period.

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Ontario, NY, United States of America

Randall J Stegbauer