System for optimizing data transmission associated with addressable buffer devices

Abstract

A method and a computer program for performing the method are disclosed for optimizing signals being exchanged between a host unit and an addressable-buffer peripheral device. The program optimizes an outgoing signal from the host unit by (1) creating an updated-state map representing the state of the peripheral device buffer expected to exist after processing by the peripheral device of the outgoing signal, (2) performing an exclusive-or (XOR) operation using the updated-state map and a present-state map representing the existing state of the buffer, and (3) constructing and transmitting a substitute outgoing signal which represents only changes to the buffer, and in which all premodified field flags are turned off. Position-dependent characters, such as attribute bytes are translated into nondata characters prior to incorporation into a map, and are retranslated into their original form for use in the substitute signal.

What is claimed is: .[.1. An optimizing system for a telecommunications system that includes 
     
        corresponding original symbol..]. 3. .[.The.]. .Iadd.An .Iaddend.optimizing system .[.of claim 1,.]. .Iadd.for a telecommunications systems, said telecommunications system including: (A) a host unit which exchanges data streams with a peripheral device, said data streams being routed between said host unit and said peripheral device by a signal routing unit,   (B) said peripheral device having an addressable buffer whose information contents are modifiable in response to data streams from said host unit,   (C) said data streams conforming to a protocol that supports the use of a field-attribute character sequence in a data stream to delimit a field in said addressable buffer, and that further supports premodification of a modified-data tag (MDT) in a field attribute character sequence in a data stream, whereby a set MDT indicates a field in said addressable buffer that has been modified, a premodified MDT being referred to hereinafter as a "premodified field flag,"   (D) said buffer contents including data characters and further including control codes, said optimizing system comprising:     (a) an optimizer connected to control said signal routing unit and programmed: (1) to read the information content of a data stream from the host unit prior to the routing of the data stream to the peripheral device;   (2) to generate an updated-state image representing the information contents of the peripheral device buffer that would be expected to exist after processing by the peripheral device of said data stream;   (3) to generate a data stream representing any differences in data characters, as well as any differences in control codes, between said updated-state image and a present-state image representing the information available to the optimizer about the present information contents of the peripheral device buffer; and   (4) to cause said signal routing unit to route the data stream so generated to the peripheral device in lieu of the data stream from the host unit;     (b) .Iaddend..[.wherein said optimizer is programmed.]. .Iadd.said optimizer being programmed .Iaddend.so that all premodified field flags in   
     
     
        the data stream routed to the peripheral device are turned off. .[.4.  An optimizing system for a telecommunications system, said telecommunications system including a host unit which exchanges data streams with a peripheral device, said data streams being routed between said host unit and said peripheral device by a signal routing unit,   said peripheral device having an addressable buffer whose information contents are modifiable in response to data streams from said host unit,   said buffer contents including data characters and further including control codes,   said optimizing system comprising:   a control-code translation table stored in a storage device and containing, for each control code normally represented in a data stream by an original symbol that is also usable to represent a data character, a translated symbol that is not used to represent any data character;   an optimizer connected to control said signal routing unit and to read said translation table and programmed   to read the content of an original data stream emanating from the host prior to the routing of the original data stream to the peripheral device;   to generate an updated-state image, said updated-state image representing the information contents of the buffer that would be expected to exist after processing by the peripheral device of said original data stream,     said optimizer utilizing in said updated-state image generation the translated symbol for any control code having a translated symbol instead of the corresponding original symbol for said control code;   to generate a modified data stream, said modified data stream representing any differences in data characters, as well as any differences in control codes, between said updated-state image and a present-state image representing the information available to the optimizer about the present information contents of the peripheral device buffer,   the optimizer utilizing in said modified data stream generation the original symbol for any control code having a translated symbol; and     to cause said signal routing unit to route the modified data stream to the peripheral device in lieu of the original data stream from the host unit..]. .[.5. The optimizing system of claim 4, wherein said optimizer is programmed to incorporate a device-control message in the modified data stream that when processed by the peripheral device, causes a data stream subsequently initiated by the peripheral device to be sent as a data stream representing changes to the peripheral device buffer that were caused at the device since the last data stream initiated by the peripheral device..]. .[.6. A method for optimizing the exchange of data streams between a host unit and a peripheral device,   said data streams being routed between the host unit and the peripheral device by a signal routing unit,   said peripheral device having an addressable buffer whose information contents are modifiable in response to data streams from said host unit,   said buffer contents including data characters and further including control codes,   said method comprising the steps of:   reading the information content of a data stream from the host prior to the routing of the data stream to the device;   generating an image representing the updated state of the buffer, said updated-state being the state that would be expected to exist after processing by the peripheral device of said data stream;   generating a substitute data stream representing both any differences in data characters and any differences in control codes between said updated-state image and an image representing the information available to the optimizer about the present information content of the peripheral device buffer; and   sending the substitute data stream so generated to the peripheral device in   
     
     
        lieu of the original data stream..]. .[.7.  An optimizing system for a telecommunications system, said telecommunications system including a host unit which exchanges data streams with a peripheral device, said data streams being routed between the host unit and the peripheral device by a signal routing unit,   said peripheral device having an addressable buffer whose information contents are modifiable in response to data streams from said host unit,   said buffer contents including data characters and further including control codes, said optimizing system comprising:     a control-code translation table, said translation table containing, for each control code normally represented in a data stream by an original symbol that is also usable to represent a data character, a translated symbol that is not used to represent any data character;   an optimizer connected to control said signal routing unit and to read said translation table and programmed to read the content of an original data stream emanating from the host unit prior to the routing of the data stream to the peripheral device;   to generate an updated-state image, said updated-state image representing the information contents of the buffer that would be expected to exist after processing by the peripheral device of said data stream,   said optimizer utilizing in said updated-state image generation the translated symbol for any control code having a translated symbol instead of the corresponding original symbol for that control code;     to generate a modified data stream; said modified data stream representing any differences in data characters as well as any       differences in control codes, between said updated-state image and a present-state image representing the information available to the optimizer about the present information content of the peripheral device buffer, the computer utilizing in said modified data stream generation the original symbol for any control code having a translated symbol instead of the corresponding translated symbol;   to cause said signal routing unit to route the modified data stream to the peripheral device in lieu of the original data stream from the host unit;   to read an incoming data stream from said peripheral device; and   to update said present-state image to reflect changes signified by said     
     
     
        incoming data stream..]. .[.8.  A method for optimizing the exchange of data streams between a host unit and a peripheral device, said data streams being routed between the peripheral device and the host unit by a signal routing unit,   said peripheral device having an addressable buffer whose contents are modified in response to data streams from said host unit,   said buffer contents including data characters and further including control codes, said method comprising the steps of:     reading the content of a data stream from the host unit prior to the routing of the data stream to the peripheral device;   generating an image representing the updated state of the buffer, said updated state being the state that would be expected to exist after processing by the peripheral device of said data stream;   generating a substitute data stream representing both any differences in data characters and any differences in control codes between said updated-state image and an image representing the information available to the optimizer   about the present information content of the peripheral device buffer,   sending the data stream so generated to the peripheral device in lieu of the original data stream;   reading an incoming data stream from said peripheral device; and   updating said present-state image to reflect changes signified by said incoming data stream..]. .[.9. A modified data stream for transmission in a telecommunications system, said system including:   a host unit which exchanges data streams with a peripheral device,   said data streams being routed between the host unit and the peripheral device by a signal routing unit,   said peripheral device having an addressable buffer whose contents are modifiable in response to data streams from the host unit,   said buffer contents including data characters and further including control codes, said modified data stream produced by a process comprising the steps of:     reading the information content of a data stream from the host unit prior to the transmission of the data stream to the peripheral device;   generating an image representing the updated state of the buffer, said updated state being the state that would be expected to exist after processing by the peripheral device of said data stream; and   generating a modified data stream representing both any differences in data characters and any differences in control codes between (a) said updated-state image and (b) an image representing information known about the present information content of the peripheral device buffer..].   
     
     
        .[.     The modified data stream of claim 9 wherein said step of reading the information content of a data stream from the host unit prior to the transmission of the data stream to the peripheral device is performed by a programmed computer..]. .[.11. The modified data stream of claim 9 wherein said step of generating an image representing the updated state of the buffer is performed by a programmable computer..]. .[.12. The modified data stream of claim 9 wherein said step of generating a modified data stream representing both any differences in data characters and any differences in control codes between (a) said updated-state image and (b) an image representing information known about the present information content of the peripheral device buffer, is performed by a programmed computer..]. .[.13. The modified data stream of claim 9 wherein said modified data stream is sent to the peripheral device in lieu of the data 
     
     
        stream from the host unit..]. .Iadd.14.  An optimizing system for a telecommunications system, said telecommunications system including: (A) a host unit which exchanges data streams with a peripheral device, said data streams being routed between said host unit and said peripheral device by a signal routing unit,   (B) said peripheral device having an addressable buffer whose information contents are modifiable in response to data streams from said host unit,   (C) said data streams conforming to a protocol that supports the use of a field attribute character sequence in a data stream to delimit a field in said addressable buffer, and that further supports premodification of a modified-data tag (MDT) in a field attribute character sequence in a data stream, whereby a set MDT indicates a field in said addressable buffer that has been modified, a premodified MDT being referred to hereinafter as a "premodified field flag,"   (D) said buffer contents including data characters and further including control codes,   said optimizing system comprising:   (a) a control-code translation table stored in a storage device and containing, for each control code normally represented in a data stream by an original symbol that is also usable to represent a data character, a translated symbol that is not used to represent any data character;   (b) an optimizer connected to control said signal routing unit and to read said translation table and programmed: (1) to read the content of an original data stream emanating from the host unit prior to the routing of the original data stream to the peripheral device;   (2) to generate an updated-state image, said updated-state image representing the information contents of the buffer that would be expected to exist after processing by the peripheral device of said original data stream, said optimizer utilizing in said updated-state image generation the translated symbol for any control code having a translated symbol instead of the corresponding original symbol for said control code;   (3) to generate a substitute data stream, said substitute data stream representing any differences in data characters, as well as any differences in control codes, between said updated-state image and a present-state image representing the information available to the optimizer about the present information contents of the peripheral device buffer, the optimizer utilizing in said substitute data stream generation the original symbol for any control code having a translated symbol; and   (4) to cause said signal routing unit to route the substitute data stream to the peripheral device in lieu of the original data stream from the host unit;     (c) wherein said optimizer is programmed to turn off all premodified field flags in the substitute data stream and thereby to incorporate a device-control message in the modified data stream that, when processed by the peripheral device, causes a data stream subsequently initiated by the peripheral device to be sent as a data stream representing changes to the peripheral device buffer that were caused at the device since the last data stream initiated by the peripheral device. .Iaddend.