Abstract: A compression apparatus for compressing a digital image is disclosed and includes a decomposer, a transform encoder unit and a merge plane compressor. The digital image is converted by the compression apparatus into a set of tiles suitable for transform encoding. Each tile from the set is then compressed by converting the tile into a “merge plane data string” and an associated “transform encoded data string”. The merge plane data string describes only the spatial locations of the background pixels in the tile. The transform encoded data describes the tile in the frequency domain but without the spatial frequencies associated with the background pixels. One important use of the present invention is to compress digital images prior to transmitting the digital image to a printer for printing.

Abstract: Compression apparatus is described that operates to select an optimum compression procedure to apply to received image data. The compression apparatus can be employed in a page printer having a print engine that must be provided with video data at a constant rate in order to avoid a print underrun. The page printer operates to receive print data and to convert the received print data into rasterized page strips. Some or all of these rasteized page strips can then be compressed by the compression apparatus for later conversion to video data. The compression apparatus operates to compress each received rasterized page strip by selecting a compression procedure that results in a compressed strip that will provide optimum print quality while not causing a print underrun and that is below a threshold data size.

Abstract: A computer is provided that monitors one or more printers over a network in order to determine when new components in each of the printers should be replaced. Each time a printer prints a document, the printer sends a signal to the computer. The computer responds by querying the printer to determine if a components in the printer should be replaced. In addition, each printer is configured to transmit a message to the printer indicating that the component should be replaced. If the computer determines that a component should be replaced, the computer can automatically transmit an order for a new component to a vendor.

Abstract: Disclosed is a printer for receiving a print job from a document processing device The print job including a preamble section, print data describing a single copy of a document and a trailer section. The trailer section including a command indicating the number of copies that are to be printed. The printer is adapted to receive the print job and operates to print the copies indicated by the command.

Abstract: Apparatus for writing compressed data to a storage device having multiple storage areas. The apparatus identifies one or more storage areas to receive the compressed data based upon the compression ratio of the compressed data and the characteristic transfer rates of the storage areas. The apparatus then writes the compressed data to the Identified storage areas. This is accomplished so that when the compressed data is later read, the storage device has at least a minimum output rate. The storage device may, for example, be a disk storage unit for a laser printer. The compressed data may be compressed video data describing a document to be printed.

Abstract: A test system for testing a multitasking computing device, such as a RAID storage device is described. The multitasking computing device is responsive to an inject fault command by entering a pre-determined mode of operation wherein the device maintains its present state and all command processing is terminated. As a result, the device becomes non-responsive to further commands. The test system includes a plurality of test programs. Each of the test programs being operable, when executed, to (a) test an associated function of the device and (b) transmit the inject fault command to the device if the test fails. In addition, each program is further operable, when executed, to (c) discontinue testing the device if the device becomes non-responsive. The test system further includes a processor and a multitasking operating system for executing the test programs concurrently.

Abstract: A RAID data storage system includes a heterogenous disk array coupled to a controller. The disk array provides a storage space that includes a first set of stipes each having at least “N” blocks and a second set of stripes each having less than “N” blocks. The controller can operate to map the storage space into redundant units by creating at least one redundant unit for storing data according to a mirror redundancy scheme. The redundant unit includes a block from the first set of stripes and a block from the second set of stripes.

Abstract: A computer operable to encode a string of tokens is described. The computer operates to identify a group of tokens in the string. The identified group of tokens are those tokens that follow a token having a first value. The computer further operates to assign a Huffman codeword to each token value present in the group. The Huffman codewords are assigned based upon the local frequencies of the group. The computer then operates to replace each token in the group with the codeword assigned to its value. The computer further operates to replace each token that is not a member of group with a codeword so as to generate a string of Huffman codewords that is representative of the string of tokens.

Abstract: A computer for compressing a digital image. The computer is operable to decompose a digital image into a set of tiles and to classify certain tiles from the set as being low detail tiles. The computer is further operable to transform each tile from the set of tiles into a series of basis function coefficients to represent the tile in the frequency domain. The computer is responsive to a tile having more than four different pixel values and classified as a low detail tile by transforming the tile into a first series of basis function coefficients. The first series of basis function coefficients includes only four coefficients that have a non-zero value.

Abstract: A computer operable to encode a string of tokens is described. The string of tokens includes a group of tokens that immediately follow a token having a first value. The Computer operates to select a token value that occurs most often in the group. The computer can then operate to convert the first string of tokens into a second string of tokens by substituting each occurrence of a token-pair unit in the first string with a single token. The token-pair unit includes a first token having the first value and a second token having the selected value. The computer then operates to identify a group of tokens in the second string. The identified group of tokens are those tokens that follow a token having the first value. The computer then operates to Huffman encode the second string. In part, this is accomplished by Huffman encoding the identified group based upon the identified group's local frequencies.

Abstract: The present disclosure describes techniques that can be used to reduce the time required for a printer or printing system to generate printed output. Printers are provided that operate to move from an idle mode into a print mode upon receiving a PRE-START signal. Printers are also provided that operate to remain in a print mode for an extended period of time upon receiving a PRE-START signal. The PRE-START signal is a signal that indicates one or more “pre-print”acts have been performed. In addition, printing systems are provided that include peripheral devices adapted to transmit a PRE-START signal to a printer upon the detection of one or more PRE-PRINT acts.

Abstract: Image forming system for arranging a plurality of images onto a selected display medium. The image forming system provides capability to determine an optimized layout pattern for one or more sub-pages on a designated print medium. This system may be used to provide expanded N-UP printing capability.

Abstract: A system to determine the length of time, known as the latency time, that is required to wait between transmitting and receiving data for a half-duplex electromagnetic transceiver having a transmitter and receiver wherein the receiver is electromagnetically coupled to the transmitter. The determination of the latency time is accomplished by the use of a control circuit that operates to turn the transmitter to an on state. The control circuit then monitors the receiver to determine when the receiver also goes to an on state due to the electromagnetic coupling. The control circuit subsequently turns off the transmitter and the length of time for the receiver to recover to an off state is measured. This length of time is the latency time and is used in subsequent transmission of data.

Abstract: Apparatus and method for storing retrievable boundary information into a buffer memory of a receiving device. In one arrangement, the boundary information is used to indicate where a block of data ends in the buffer memory. In another arrangement, the boundary information is used to indicate where a burst begins and ends in the buffer memory. This is accomplished by the use of boundary indicators and following a set of organization rules as data and boundary indicators are written into the buffer memory. As a result, during a later buffer read operation the data and the boundary information can be retrieved and identified.

Abstract: A system for managing burst data transfers from a sending device to the buffer memory of a receiving device and for managing read operations upon the buffer memory after receiving data. In one arrangement, the system includes data management apparatus that is used in a tape storage device. The data management apparatus uses a Start of Burst pointer, a Current Position pointer and a Tape Mechanism pointer to simplify several functions. These functions include the determination of whether to enable a burst from a sending device and the determination of whether to perform a series of read operations upon the buffer memory. In addition, the Start of Burst pointer and the Current Position pointer are used to re-write a burst into the buffer memory if a previously received burst is determined to be invalid.

Abstract: Apparatus and method for compressing Huffman encoded data. The compression apparatus includes a string detector and a record generator. The compression apparatus operates to receive the Huffman encoded data and the length of the codewords used to generate the Huffman encoded data. The string detector then operates to detect each set of repeating strings and each non-repeating string in the encoded data. Each set of repeating strings is replaced with a record that indicates the length of the repeating string, the number of repeats and an instantiation of the repeating string. In addition, each non-repeating string is replaced with a record that indicates the length of the non-repeating string and the non-repeating string. The resulting compressed Huffman data can then be transmitted to a printer.

Abstract: A system for reducing memory resources required to process a print job having common page print data. Reduction of memory resources is accomplished by first analyzing pages from an application for common page aspects and unique page aspects. The common page aspects are then converted to common page print data and the unique page aspects are converted to unique page print data. The common page print data is identified in a manner allowing for an optimized form of the common page print data to be created. An optimized form of the common page print data is then created and stored. The common page print data is merged with the unique page print data in an appropriate manner. Each page is then printed. The invention has particular benefits for presentation applications using the same background for each page in a set. Other applications can also benefit.

Abstract: A tape block and take-up reel assembly for use in a non-continuous cartridge based magnetic tape transport system. The take-up reel assembly includes a leader tape and a leader block. The tape block connection features and the leader block receiving features allow for a connection to be established therebetween as a result of orienting the tape block and leader block from a pre-connective orientation to a pre-connective mated orientation. These orientations are primarily achieved by moving the cartridge into the tape transport system and by winding the take-up reel assembly.

Abstract: A multiple media sheet stack selection mechanism for selectively presenting multiple media sheet stacks to the same sheet separation and feed mechanism. The multiple media stack selection mechanism includes a primary sheet holder and at least one secondary stack holder. In the first embodiment, the multiple media stack selection mechanism includes a rotatable feed arm mechanism for holding the second paper stack and for positioning the second paper stack for picking and advancement. In the second embodiment, the multiple media sheet stack selection mechanism includes a paper stack gripping device for holding a second paper stack and for positioning the second paper stack for picking and advancement. In both the first and second embodiment, the paper stacks are positioned at a near vertical angle. The near vertical angle provides additional advantages in that the gravity force assists in constantly urging the sheets toward the feed zone, and results in a greater feed reliability.

Abstract: A threading apparatus for threading tape from a single reel magnetic tape cartridge through a tape transport machine. The threading apparatus includes a leader block and a take-up reel. The take-up reel includes a leader block receiving section that is adapted to receive the leader block during a threading operation. Upon the take-up reel receiving the leader block, the take-up reel and leader block form a smooth winding substrate for subsequent wraps of magnetic tape.