Abstract: In rows (1) of data elements (11, 12), there may occur special data elements, such as control characters. By replacing each special data element (12) by a replacement data element (14), which contains a positional indication of a next special data element (12′) and which does not correspond to a special data element (12), it is possible to reproducibly remove all special data-elements from the row (1) without the length of the row increasing essentially. only one single supplementary data element (13) is required for transmitting the positional indication of the first special data element.

Abstract: An endian conversion apparatus includes a first switch. The first switch inputs an input byte data, a data size signal, an endian switch signal and a byte enable data to output an output byte data on which a second endian representation is performed. The input byte data includes a plurality of byte data on which a first endian representation is performed. The data size signal indicates the number of bytes to be recognized as a unit data. The endian switch signal indicates an execution of an endian conversion. The byte enable data indicates a byte position to be recognized as the unit data. The first endian representation is performed on the byte enable data. The first switch outputs the output byte data having the number of bytes indicated by the data size signal when the endian switch signal indicates the execution. An array of the byte position indicated by the byte enable data is maintained in the output byte data.

Abstract: There are provided coding and decoding apparatuses and coding and decoding methods in which digital data are represented by bits fewer than those by which digital data according to the prior art apparatuses and methods are represented, and original data can be decoded correctly without degrading its precision. The number of continuous zeros from the LSB of the digital data 103 is counted. The number on continuous zeros plus one is subtracted from the number of bits of the digital data 103, resulting in a number of bits to-be-allocated 105, according to which, bits are allocated starting from the most significant bit (MSB). The number of omitted bits is calculated according to the number 105 (114), and lower bits represented as the MSB “1” and bits “0”. The lower bits 116 are coupled to a lower side of a code 115 to restore original digital data 151.

Abstract: A p-to-q (p<q) code table, and a p-to-q modulation method and system that uses the table and provides a q-bit code stream satisfying a predetermined RLL constraints and the DSV constraint and including no merging bit are provided. The table comprises a plurality of subtables with respective ID's. Each q-bit code in the table is accompanied with a field containing a subtable ID for the modulation of the next code. Codes can be used repeatedly in each subtable such that combinations of appearances of each of the overlapping codes and respective fields are unique in the subtable.

Abstract: Differential signaling between integrated circuit chips uses fewer than 2 external wires per bit transmitted. Rather than pairing wires into groups of two, the external wires are part of a larger group of 2i+2 wires. Half of the wires in the group are driven low while the other half of the wires are driven high. Since the wires are not paired, adjacent wires can have the same logical state. Differential comparators in the receiver chip compare each wire with all other wires in the group. All outputs of comparators that have a wire as one of its two inputs are input to a majority logic block that evaluates the logical state of the wire. Since half of the wires are in one state, the majority of the remaining wires are in the opposite state of the wire being evaluated. Thus the majority of the comparator outputs indicate the opposite state of the wire being evaluated.

Abstract: A plurality of serial data streams are transmitted on a corresponding plurality of lines at a common frequency in equal groups of symbols. A framing signal composed of groups of symbols corresponding in number to groups of data symbols is transmitted on an additional control line. Each group of symbols in the framing signal includes a majority of symbols capable of representing a first plurality of code words and a second plurality, substantially less than the first plurality, of valid code words, and a minority of symbols which constitute parity check symbols. Each of the valid code words consists of a first sub-group of similar symbols and a second plurality of similar symbols. For some of the valid code words the symbols in the first sub-group are similar to the symbols in the second sub-group. For other valid code words the symbols in the first sub-group are different from the symbols in the second sub-group.

Abstract: A method and apparatus for converting digital data representations, such as network addresses of different computer networks. Input data, which in one embodiment includes a hexadecimal network address, contains a plurality of bytes, with each byte having a plurality of digits arranged in positions. A first set of digits from the bytes is selected having a first digit position. The digits in the first set are shifted to a second digit position to generate a first resultant. A second set of digits is selected having a third digit position. The digits in the second set are shifted to a fourth digit position to generate a second resultant. The first and second resultants are summed to generate a converted output network address.

Abstract: The invention concerns a data encoding/decoding process. In the encoding process, data are converted from a decoded state into an encoded state in which: the data, both in the encoded state and in the decoded state, are in the form of a stream of binary information, by processing the decoded string of data from left to right, its current prefix and the next binary information being considered, a list of binary patterns being registered, in which for each is emphasized the last binary information and the corresponding prefix, a comparison is made between the current prefix of the decoded string and the prefixes of registered patterns. The list of patterns is a set of patterns that do not occur and when a prefix of the decoded string matches with a prefix of a registered pattern, the next binary information of the decoded string is omitted from the decoded stream to make the encoded stream.

Abstract: The apparent speed of a connection between a browser at a user station and a proxy or gateway on a network such as the Internet is increased by providing a local proxy at the user station which interacts with a remote proxy. While the remote proxy is retrieving a newly requested World Wide Web page, for example, from the appropriate content provider, it may also be sending to the local proxy a stale cached version of that page. When the new version of the page is finally retrieved, the remote proxy determines the differences between the new version and the stale version, and, assuming the differences do not exceed the new page in size, sends the differences to the local proxy which then reconstructs the new page from the differences and the stale version. The local proxy delivers the new page to the browser, which need not even be aware that a local proxy exists; it is aware only that it received the page it requested.

Abstract: The four tables P, Q, R and S contained in an ROM 2 for 16-24 modulation have a total number of data in which the continuing bits are 2 bits, that is not larger than i bits among the 24 bits, so that the number of continuing bits having the same code is from 2 to 8 bits, so as to have the same characteristics as the (1, 7) code, and to stably lock the PLL. A comparator/selector circuit 5 selects an optimum table out of the tables P, Q, R and S.

Abstract: The method of the present invention aligns a set of N sequences, where N is large. The alignment brings out the best commonality of the N sequences. The method is performed in two stages. A first stage involving discovering motifs, and a second stage involve motif pruning and sequence alignment. The present invention also provides an additional constraint, K, as a user defined control parameter. The additional parameter constrains the alignment of the N sequences to have at least K of the N sequences agree on a character, whenever possible, in the alignment. The alignment number, K, provides a natural constraint for dealing with a large number of sequences in that a commonality across most, if not all sequences is required to be detected.

Abstract: An analog to digital voice transmitter which converts analog voice to digital voice data. The transmitter contains a converter for converting digital voice data which corresponds to control data codes, to non-control data. In one embodiment, an ADPCM encoder encodes inputted analog voice signals to ADPCM digital voice codes. A S/P converter converts serial signals to parallel signals of the byte unit. A code converter detects codes to be removed which exist in the ADPCM data of the byte unit and converts the codes to be removed to a code not to be removed by adding or subtracting a data value of 1 to the code to be removed. A transmission FIFO memory stores the ADPCM data in order. A P/S converter converts the parallel data of the byte unit to the serial signals. A transmitting section transmits the serial data in infrared rays to a receiver.

Abstract: To improve the speed of transition to the zero-volt suspend state, system context is saved from volatile random access memory to non-volatile memory, such as a hard disk, using a compression algorithm which speeds the transfer of data to non-volatile memory by recognizing data pages having bytes of a single value. The system context in extended memory of RAM consists of a number of system context memory blocks, and between these memory blocks are memory holes containing information which does not require storage. Initially, the entirety of data in a buffer region of RAM is stored directly to disk. Then, successive pages from each system context memory block are transferred to the buffer, where the page size corresponds to the memory management unit page size. When testing locates a region of heterogeneous entries, then a heterogeneous-data flag, the length of the heterogeneous region, and the heterogeneous data region are transferred to the buffer.

Abstract: Image data is transmitted from a memory to a CPU (central processing unit). A transmission circuit of the memory receives an 8-bit source parallel signal, makes reference to transmission histories or to transmission predictions to generate a 2-bit coded parallel signal from the source parallel signal, and sends a serial signal as a result of converting the coded parallel signal, together with a flag signal indicative of the presence of an encoding. If the source parallel signal remains unchanged, the coded parallel signal is made to indicate 00 so that the bit transition probability of the serial signal is reduced. A reception circuit of the CPU receives the serial and flag signals and restores the 8-bit source parallel signal on the basis of reception histories or on the basis of reception predictions.

Abstract: A lossless bandwidth compression method for use in a distributed processor system for communicating graphical text data from a remote application server to a user workstation over a low bandwidth transport mechanism enables the workstation display to support the illusion that the application program is running locally rather than at the remote application server. At the application server, the graphical text data is represented by a string of glyphs, each glyph being a bit mask representing the foreground/background state of the graphical text data pixels. Each unique glyph is encoded by assigning a unique identification code (IDC). Each IDC is compared with the previous IDCs in the string and, if a match is found, the IDC is transmitted to the workstation. If a match with a prior IDC is not found, the IDC and the corresponding glyph pattern are transmitted to the workstation.

Abstract: A computer-readable medium includes computer-executable instruction for compressing data to form a compressed data stream for a restricted channel. Specifically, data is compressed to form code values and character values, and a mask is created that indicates the location of these code values and character values in the compressed data stream. Each mask constructed by the method is selected from a set of valid values that can pass through the restricted channel.

Abstract: An apparatus for transmitting a digital information signal includes an input terminal for receiving the digital information signal, a first channel encoding unit for carrying out a first channel encoding step on an information word in a series of subsequent information words included in the digital information signal so as to obtain a channel word, a compression unit for carrying out a compression step on a channel word so as to obtain a compressed channel word, an error correction encoding unit for carrying out an error correction encoding of the compressed channel word so as to obtain a parity word, a second channel encoding unit for carrying out a second channel encoding step on the parity word so as to obtain a channel encoded parity word, and a formatting unit for combining the channel word and the channel encoded parity word into a composite transmission signal suitable for transmission via a transmission medium.

Abstract: It is intended to provide a buffer control method which performs control by deciding if data should be held in buffer, thereby enabling to reuse the data stored in the buffer. This method has the following steps of: storing data in a buffer; receiving, as an input, expiration time information indicating a time to stop holding the data; comparing time clock information indicating a time clock of a decoding apparatus with the expiration time information; and controlling the holding of the data within the buffer according to the comparison.

Abstract: A digital data coding/decoding method and apparatus are provided. The coding method includes the steps of representing respective digital data by digits of a predetermined same number, and coding the digital data represented by digits of the same number by a predetermined coding method from the uppermost significant digit sequence to the least significant digit sequence. The method for decoding digital data coded in the order of significance by rating the significance of digits of the digital data, includes the steps of analyzing significance of coded digital data, and decoding the analyzed digital data from upper significant digits to lower significant digits by a predetermined decoding method. Even if some bitstreams are lost or damaged by coding important information first, deterioration in audio quality can be reduced.

Abstract: A digital data coding/decoding method and apparatus are provided. The coding method includes the steps of representing respective digital data by digits of a predetermined same number, and coding the digital data represented by digits of the same number by a predetermined coding method from the uppermost significant digit sequence to the least significant digit sequence. The method for decoding digital data coded in the order of significance by rating the significance of digits of the digital data, includes the steps of analyzing significance of coded digital data, and decoding the analyzed digital data from upper significant digits to lower significant digits by a predetermined decoding method. Even if some bitstreams are lost or damaged by coding important information first, deterioration in audio quality can be reduced.

Abstract: The method of the present invention discovers patterns in an sequence of characters in two phases. In a sampling phase, preferably proper templates corresponding to the sequence of characters are generated. Patterns are then generated corresponding to the templates and stored in memory. In a convolution phase, the patterns stored in memory are combined to identify a set of maximal patterns. A subset of the maximal patterns is selected. Compressed data representing the sequence of characters is generated. The compressed data includes first data data representing each selected pattern of the subset, and second data representing the sequence of characters wherein occurrences of each selected pattern within the sequence of characters is replaced by a reference to first data corresponding to the selected pattern. The method is useful in compressing information stored in a database or compressing information communicated over a communication link.

Abstract: A method of compressing data, including representations of objects, for future transmission or storage. More specifically, this invention compresses a representation of differences between a base sequence of data and the actual data to be transmitted or stored. Sparse bit masks representing the positions of insertions and deletions from a base sequence are iteratively compressed by representing consecutive sequences of zero-valued bits with single zero-valued bits.

Abstract: A method of compressing letters adapted to store a letter in a specific bit and a memory unit includes compiling a set of 26 letters of the English alphabet and dividing it into two halves, which are respectively encoded as headers or tailers. Headers are stored in the specific bit, while tailers are stored in the memory unit, so as to reduce memory spaces. By using the method in combination with a speciaily designed data structure, 16 letters may be stored in 10 bits.

Abstract: A data processing device is programmed to decode and transform a stream of data representing a plurality of subband encoded channels of audio data into one or more channels of PCM encoded data for reproduction by a speaker subsystem. An improved method for decoding and transforming utilizes downmix matrices (1021 and 1022) to form downmixed frequency domain channels in buffers (1031-1034). Only two long DCT transform operations (1041 and 1042) and two short DCT transform operations (1043 and 1044) are needed to transform the downmixed frequency domain channels into a left PCM output (1071) and a right PCM output (1072).

Abstract: The apparent speed of a connection between a browser at a user station and a proxy or gateway on a network such as the Internet is increased by providing a local proxy at the user station which interacts with a remote proxy. While the remote proxy is retrieving a newly requested World Wide Web page, for example, from the appropriate content provider, it may also be sending to the local proxy a stale cached version of that page. When the new version of the page is finally retrieved, the remote proxy determines the differences between the new version and the stale version, and, assuming the differences do not exceed the new page in size, sends the differences to the local proxy which then reconstructs the new page from the differences and the stale version. The local proxy delivers the new page to the browser, which need not even be aware that a local proxy exists; it is aware only that it received the page it requested.

Abstract: Characters that are not among those recognized for use in page messages are encoded using a subset of the recognized printable characters to enable the data comprising a page object to be transmitted over a paging channel. In one preferred form of the invention, a subset of the recognized printable characters are designated as encoding characters for use in encoding data that includes characters not among the recognized printable character set. Further, each time that one of the encoding characters occurs in the input data, the byte representing that character must also be encoded. To encode the characters, the byte is divided into nibbles. Each nibble is a hexadecimal digit that is encoded using one of the 16 encoding characters. If a byte of the input data repeats more than four times in succession, it is run length encoded (RLE) during the encoding process to compress the encoded data.

Abstract: Each character in a message is segregated into a range depending on the value of the character and encoded based on the range of the character. The encoding techniques may include removing all but the lowest byte, removing all but the lowest byte and masking one or more bits, base 64 encoding, base 64 encoding certain bits, and subtracting prior to base 64 encoding certain bits. To certain encoded characters is added a shift character, which can be used to determine how to decode the character. Multiple characters in the same range may be encoded and placed between a shift lock character and a shift unlock character, with the shift lock character used to determine how to decode the encoded characters. The encoded characters may be decoded using the encoded character, and the absence or presence of any shift, shift lock or shift unlock characters.

Abstract: Disclosed is a coding technique which takes advantage of the use of an internal synchronization technique for a timing-based servo which employs alternating 4 and 5 transition bursts of servo to provide a simplified synchronization of the data, and comprises a coding technique which employs a periodic pattern of bursts each period comprising two bursts of 5 transitions followed by two bursts of 4 transitions. The code provides, in each burst of 5 transitions, two defined positions for the 2nd and 4th transitions, spaced from equally spaced positions in the burst, to represent each of two bit values. The code provides, in each burst of 4 transitions, two defined positions for the 2nd and 3rd transitions, spaced from equally spaced positions in the burst, to represent each of two bit values.

Abstract: A data translating memory system useful in a liquid ink printer. The data translating memory system is organized such that the process of writing information and the process of reading the information causes a reorganization of the information. The memory includes memory cells, for storing bit signals, a first selection bus, coupled to a first plurality of groups of the memory cells for selection thereof, a first data bus, coupled to the first plurality of groups of memory cells, for transmitting bit signals, a second selection bus, coupled to a second plurality of groups of the memory cells for selection thereof, the second plurality of groups of the memory cells being different than the first plurality of groups of the memory cells, and a second data bus, coupled to the second plurality of groups of memory cells for transmitting bit signals.

Abstract: An adaptive display refresh and data compression solution for use in an RF network environment is described, where a network controller and portable terminals maintain an adaptive history of commonly used past information in order that it may be repeated quickly and communication speeds can be increased. A network controller maintains a separate history for each of the terminals in the RF network, and transmits a coded reference for the activities that are contained in the history, which is stored in the memory of both the controller and the portable terminal. Terminals and the controller additionally may negotiate to determine the data compression features which will be supported in communication between the two devices. Data is compressed according to the present invention by utilizing a hybrid run length and sliding dictionary compression scheme.

Abstract: A method generates a reduced number of values representing a sequence of grouped data values and partitions the reduced number of values by first mapping data values into groups of symbols and then partitioning the resulting stream of symbols. The digits representing the first data value in each group are replaced with symbols from a first alphabet. The most significant digit of the second data value in each group and the sign of that second data value are also represented by a symbol from the first symbol set, while the remaining significant bits of the second data value in each group are represented by symbols from a second symbol set. A stream of symbols which represent a sequence of grouped data values is partitioned into first partition symbol groups and second partition symbol groups. Each first partition symbol group comprises the symbols representing the first data value in each group and also the symbol representing the least significant bit of the second data value which follows.

Abstract: The present invention discloses a mathematical technique which finds substantial utility in electrical engineering, particularly in the general field of data transformation, which occurs in applications such as data encryption and data compression. The technique uses a commencement matrix to transform a first number of a sequence of numbers. This initial transformation forms a forward resultant matrix. Successive transformation of succeeding numbers in the sequence produces for each number in the sequence an augmented forward resultant matrix. Each augmented forward resultant matrix is used to transform the next succeeding number of the sequence, and so on. A final transformed sequence is generated from the final form of the augmented forward resultant matrix.

Abstract: The invention doubles the bit rate for a given media bandwidth as compared to, for example, Manchester encoding. It is applicable to serial transmission or storage of digital data. An arbitrary NRZ data stream is first encoded by a pre-encoding method, such as Manchester, that combines clock and data to represent a single NRZ bit in one clock cycle. A toggle flip flop then re-encodes the pre-encoded waveform, thus generating a double toggle (DT) encoded waveform, which spreads the spectral energy over a larger bandwidth and encodes two NRZ data bits within one transmission clock cycle. In the case of Manchester pre-encoding, data is decoded by determining if there are transitions nearly synchronous with an edge of the recovered clock. For other pre-encoding methods, decoded data is determined by the length of the transition period and the edge polarity of the recovered clock at the leading edge of the transition within the DT encoded waveform.

Abstract: In a method and system for storing a plurality of data blocks in a memory device, blocks of data elements are stored in a two-dimensional address space such that blocks overlap in the address space. The data elements may be digital words which represent exponents of a polynomial expansion. An overlapping data block is segmented into sub-blocks which are separated by null regions. Common data elements that are shared among the blocks are non-redundantly stored in the memory device.

Abstract: A method for compressing a data stream, where a first portion of the data stream is read into a window having a history buffer and look-ahead buffer. An index, based on a fourth portion of the data stream in the look-ahead buffer is used to select an entry in a pointer array. An initial entry in a record array is selected based on the pointer array entry. A third portion of the data stream is selected. The third portion is compared to a second portion in the look-ahead buffer. If the third portion does not match the second portion, then a subsequent entry in the record array is selected, and the is designated as the initial entry. These steps are repeated until either the third portion matches the second portion, or no more entries are left in the record array. When there are no more entries left in the record array, the second portion is written to the output file, and the first portion read into the window is incremented by a predetermined amount.

Abstract: A method for compressing digital image of more than a first predetermined number into the first predetermined number of bits in a substantially lossless manner includes determining a plurality of ranges in which input image data falls and comparing current image data with the plurality of ranges. The method further includes preserving a second predetermined number of bits of the current image data based upon which of the plurality of ranges the current image data falls to encode the current image data as an image value comprising the first predetermined number of bits.A system includes means for determining a plurality of ranges in which input image data falls and means for comparing current image data with the plurality of ranges, the means for comparing coupled to the means for determining.

Abstract: The decimal numbers in ASCII code are converted into base n number codes, where the base n is greater than ten, and then are transmitted between the main control unit and the terminals including servo systems and spindle systems in an automated factory system. The data is thus compressed, and greater number of axes of the numerically controlled devices, etc., can be controlled within a predetermined time length for transmitting the data.

Abstract: A system and method for storing variable length objects such that memory fragmentation is reduced, while avoiding the need for memory reorganization. A remainder of a variable length object may be assigned to share a fixed-size block of storage with a remainder from another variable length object (two such remainders which share a block are referred to as roommates) on a best fit or first fit basis. One remainder is stored at one end of the block, while the other remainder is stored at the other end of the block. The variable length objects which are to share a block of storage are selected from the same cohort. Thus, there is some association between the objects. This association may be that the objects are from the same page or are in some linear order spanning multiple pages, as examples. Information regarding the variable length objects of a cohort, such as whether an object has a roommate, is stored in memory.

Abstract: A generalized data decompression engine is incorporated within a field programmable gate array ("FPGA"). The generalized data decompression engine uses a general purpose data decompression technique such as, for example, a Lempel-Ziv type technique. During operation, a compressed configuration bit stream is received by the generalized data decompression engine in the FPGA and is decompressed thereby. A resultant decompressed configuration bit stream is then used to program logic cells within the FPGA.

Abstract: Digital data formatting/deformatting circuits perform digital data formatting/deformatting operations separately from a digital signal processor to reduce the required time and power consumption in formatting and deformatting digital data. In the formatting operation, the data to be formatted are arranged in a line and then outputted in the unit of a desired number of bits. In the deformatting operation, the formatted data are arranged in a line and then outputted in the unit of the original number of bits.

Abstract: A method and apparatus for detecting the null byte at the end of a character string. The method and apparatus first logically concatenates two 32-bit input values into a single 64 bit value. Next, the 64-bit value is divided into 8 bytes. Then, a logical OR operation is performed on each byte and the results are put into an encoder. Finally, the encoder interprets the results of the OR operations and places output values into processor registers which indicate whether or where a null byte was detected.

Abstract: A method for communicating using a plurality of spread spectrum codes. A plurality of spreading codes are generated by use of one or more linear feedback shift registers configured with feedback taps. The spreading codes may be maximal or non-maximal. A plurality of code portions are selected, one from each of the spreading codes. The code portions each have the same length and are selected for low cross-correlation and favorable auto-correlation and spectral properties. Each of the code portions is associated with a data symbol representing a unique group of data bits. An input data stream is divided into groups of data bits and, in response thereto, the code portion associated with each group of data bits is transmitted. At the receiver, the transmitted signal is captured in one or more receive shift registers.

Abstract: A method for compressing a first bit digital input representative of first pixel data into a second bit digital output representative of second pixel data, the method comprises the steps of defining a logarithmic function for converting the first bit digital input into the second bit digital output; replacing a portion of the logarithmic function with a polynomial function; and compressing the first bit digital input into the second bit digital output by utilizing the logarithmic and polynomial function.

Abstract: Methods for compressing data including methods for compressing highly randomized data are disclosed. Nibble encode, distribution encode, and direct bit encode methods are disclosed for compressing data which is not highly randomized. A randomized data compression routine is also disclosed and is very effective for compressing data which is highly randomized. All of the compression methods disclosed operate on a bit level and accordingly are insensitive to the nature or origination of the data sought to be compressed. Accordingly, the methods of the present invention are universally applicable to any form of data regardless of its source of origination.

Abstract: A method for the transmission of line-oriented data sets. This method employs two data set structures which keep the images of the data sets at different time stages and which are filled alternatingly with the data sets. The method allows to determine updates of the data sets and avoids re-transmission of old information. In particular, moved lines are detected in a very effective manner. As a result, high update rates with low amounts of transmitted data are achieved. The method is suitable for local terminal sessions employing text or raster graphic terminals, which have to be operated from a remote site.

Abstract: A data processing system includes a head for electro-optically reading coded indicia to generate digital decoded data in a predetermined data exchange format. An interface arrangement is used for connecting the head to any selected one of a plurality of electronic devices having individual data processors. Thus, a common data exchange format is established for all the devices, and conversion circuitry is employed for converting the predetermined data exchange format to the common format. The conversion circuitry is operatively connected between the head and the selected device.

Abstract: A data compression apparatus including a circuit for receiving a data element, a storage circuit for sequentially storing previously received data elements at sequentially addressed fixed locations, a circuit for comparing the received data element to the stored data elements to determine whether the received data element matches at least one of the stored data elements, and a circuit for generating an address of the matching stored data element. In addition, a method of compressing data including the steps of receiving a data element, sequentially storing previously received data elements at sequentially addressed fixed locations, comparing the received data element to the stored data elements to determine whether the received data element matches at least one of the stored data elements, and generating an address of the matching stored data element.

Abstract: Storage and access of compressed data via separately compressed and stored fixed size logical blocks. An original uncompressed data file is divided into fixed-size logical blocks and then separately compressed thus resulting in a compressed block of data of a generally known maximum size according to a compression ratio known in advance of the actual compression. After the uncompressed fixed-size logical block has been compressed into a maximum fixed-size logical block it is stored into space allocated to it. Furthermore, a table is built correlating the original uncompressed fixed-size logical block to the sectors allocated for each maximum fixed-size compressed logical block thus providing a mapping between the original uncompressed data file and the physical location on the storage device. Alternatively, because the compression ratio is known and because the size of the uncompressed fixed-size logical blocks is known, the resulting maximum size of the compressed logical blocks is generally known.

Abstract: A coding scheme for transmitting messages particularly between computers is described. Messages are transmitted in packets which include at least a data portion and a terminator. Out of a predetermined set of symbols, sixteen data symbols and at least one control symbol is selected. The terminator token is generated to constitute the symbol and a six-bit symbol representing checking bits.

Abstract: Decoding and encoding of variable length data words and data strings is accelerated by testing for and processing more than one word or string per encoding or decoding cycle. In an encoding scheme wherein fixed length data words are encoded into variable length data strings, decoding is carried out by first receiving a data stream having a plurality of encoded data strings contained therein, and then testing at least a portion of the data stream to determine whether the portion contains one of a number of selected sets of multiple data strings. If the portion of the data stream contains one of the selected sets of multiple data strings, the multiple data strings are decoded into a corresponding set of multiple data words. This decoding procedure allows a plurality of encoded data strings to be decoded in a single decoding cycle. The procedure may be implemented using either a single lookup table or a set of split-level lookup tables.