Xerox Corporation

Kitty Sathi

Ronald A Ippolito

Colleen R Enzien

Christopher Comparetta

Ernest L Legg

Anthony M Federico

Randall J Stegbauer

Mark A Smith

Keith A May

Thomas M Frey

Jack T Latone

Richard T Lauria

Thomas B Zell

Robert J Slomcenski

David A Catapano

Lillian-Liu Hsu

Mark C Biondi

Lyssa E Menard

Gary Padlipsky

Andrew D Post

Christopher Compareta

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

A printing system for making prints from a stream of image data written in a printer page description language is provided. The stream of image data includes a compressed bitmap having break entries dividing the bitmap into a plurality of image data segments. The printing system includes an arrangement for separating the compressed bitmap from the stream of image data and a boundary code catcher, which communicates with the separating arrangement, for creating a table to list the break entries of the bitmap. A memory section is employed to store the bitmap with its corresponding break entry table, and a plurality of imaging channels, which communicate with the memory section, are employed to decompress selected segments of the bitmap in parallel.

Apparatus and method for parsing a stream of data including a bitmap and

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 printing system with plural hard disks for storing system files with booting process for booting the system to a running condition, the booting process detecting a previously replaced or misplaced disk and in response thereto, enabling booting of the system without loss or re-installing of critical system files.

Process for replacing storage media in electronic printing systems

A method is provided for preserving the integrity of a memory in an electronic printer in the event that a printed wiring board with non-volatile memory is replaced. The memory includes plural disks providing permanent data storage and the non-volatile memory communicating with the disks. In the method, a processor identifier is provided with the printed wiring board. A time stamp indicating the date of installation of the printed wiring board is generated, and the processor identifier of the printed wiring board is combined with the time stamp to provide an identifier seal. Copies of the identifier seal are stored to each of the disks. The processor identifier of the printed wiring board is compared with the processor identifiers of the respective identifier seals of the disks in response to booting the processor. When the processor identifier on the printed wiring board is substantially different from one of the processor identifiers of the disks, the printed wiring board is replaced and the transfer of data between the non-volatile memory and the disks is inhibited until the processor identifier of the replaced wiring board and the processor identifiers of the disks correspond substantially.

Process for replacing non-volatile memory in electronic printing systems

An electronic printing system with plural hard disks for storing system files in which upgraded software together with software identification data is written to a first of the disks, the system booted from the first disk, and the upgraded software thereafter migrated from the first disks to the other disks.

Process for automatically migrating a subset of updated files from the

An electronic printing system with plural hard disks for storing system files, each disk having a bad page table, from the individual disk bad page tables, generating a composite bad page table, providing a common allocation table for controlling allocation of disk file space for storing system files on the disks, and precluding allocating of system files to areas of the disks identified in the composite bad page table as being unusable.

Process for accommodating bad disk pages in an electronic printing system

An electronic printing system with plural hard disks for storing system files in which file management information is held in a Volume Allocation Table in internal system RAM memory with file management updates queued in NVM, with the contents of the Volume Allocation Table transferred to external disk memory when the queue of file management updates in NVM reaches a predetermined size.

System using the storage level of file updates in nonvolatile memory to

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.

Disk bandwidth allocations to prioritize disk requests

An electronic printing system prevents printing failures and interruptions associated with the inability of an image generation subsystem to generate a page image in digital form in real-time by reviewing the page contents prior to submission to the image generation subsystem. The quantity, size, geometry and location of objects on a page are analyzed to generate an internal intermediate description of the page. A determination is made if sufficient resources exist to perform real-time imaging. If real-time imaging cannot be performed, the page will be automatically simplified before the job containing the page is submitted for printing.

Determining the complexity of a page prior to a print attempt

A method is provided in which a volume allocation table (VAT) is constructed in a system memory on the basis of those files stored on a plurality of disks. In constructing the VAT of the system memory, contiguous (i.e., single run) files are first allocated to a first set of locations on the disks, and then non-contiguous (i.e., multiple run) files are allocated to a second set of locations on the disks. Upon building the VAT of the system memory, copies of it are written respectively to the disks so that the contiguous and non-contiguous files can be allocated to the first and second set of locations, respectively.

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Pittsford, NY, United States of America

Kitty Sathi