Method and apparatus for code conversion

Claim 2

In A system for transferring binary coded data between a cyclic display storage unit and a file storage unit of a CRT data display system wherein data is stored in said file storage unit in one code, which may be referred to as a system code, and in said cyclic display storage unit in another code, which may be referred to as a video code, and wherein a line of data in said display storage unit includes a group of binary digits between video code groups read while an intercharacter space is being produced on the CRT, the method of converting a line of data from said system code to said video code for display of a predetermined number of characters, comprising; recirculating in a data register a line of data to be transferred to said display storage unit from said file storage unit with spacing between system code groups that define characters, said spacing being sufficient to receive a related video code group, and recirculating in a dictionary register a plurality of system code groups one group for each of all possible characters each system code group followed by its related video code group; comparing each system code group in said data register with a system code group in said dictionary register during each cycle of the data register, and in response to each correlation, reading the following video code group from said dictionary register into said data register in the space following; and shifting data in said dictionary register relative to data in said data register after each cycle of said data register so that, during the next cycle, each system code group in said data register is compared with a different system code group in said dictionary register.

Claim 3

The method of claim 1 further comprising the technique of counting the number of correlations found, and when the number counted reaches the predetermined number of display characters in a line of data to be transferred, terminating the code conversion process and transferring the converted line of data to said display storage unit.

Claim 4

The method of claim 1 further comprising the technique of erasing the system data code groups in the line of converted data transferred from said data register to said display storage unit, whereby unit positions just erased in the stream of video code groups function as intercharacter space groups of binary digits.

Claim 5

The method of claim 2 further comprising the technique of counting the number of cycles of said conversion process, and indicating an error if the number of correlations found do not equal the number of display characters in a line of data before the number of cycles counted is equal to the number of video code groups stored in said dictionary register.

Claim 6

In a system for transferring binary coded data between a cyclic display storage unit and a file storage unit of a CRT data display system wherein data is stored in said file storage unit in one code, which may be referred to as a system code, and in said cyclic display storage unit in another code, which may be referred to as a video code, and wherein data in said display storage unit includes a group of binary digits between video code groups read while an intercharacter space is being produced on the CRT, the method of converting a line of a predetermined number of display characters from said video code to said system code comprising: recirculating in a data register a line of data to be transferred to said file storage unit from said display storage unit together with said intercharacter space group of binary digits between video code groups that define characters, and recirculating in a dictionary register, a plurality of video code groups, one group for each of all possible display characters, each video code group followed by its related system code group; comparing each video code group in said data register with a video code group in said dictionary register during each cycle of the data register, and in response to each correlation, reading the following system code grouP from said dictionary register into said data register in the space following; and shifting data in said dictionary register relative to data in said data register after each cycle of said data register so that during the next cycle each video code group in said data register is compared with a different video code group in said dictionary register.

Claim 7

In a system for transferring binary coded data between a cyclic display storage unit and a file storage unit of a CRT data display system wherein data is stored in said file storage unit in one code, which may be referred to as a system code, and in said cyclic display storage unit in another code, which may be referred to as a video code, and wherein data in said display storage unit includes a group of binary digits between video code groups read while an intercharacter space is being produced on the CRT, the method of converting a line of a predetermined number of display characters from said video code to said system code comprising: recirculating in a data register a line of data to be transferred to said file storage unit from said display storage unit together with said intercharacter space group of binary digits between video code groups that define characters, and recirculating in a dictionary register, a plurality of video code groups, one group for each of all possible display characters, each video code group followed by its related system code group; comparing each video code group in said data register with a video code group in said dictionary register during each cycle of the data register, and in response to each correlation, reading the following system code grouP from said dictionary register into said data register in the space following; and shifting data in said dictionary register relative to data in said data register after each cycle of said data register so that during the next cycle each video code group in said data register is compared with a different video code group in said dictionary register.

Claim 8

The method of claim 5 further comprising the technique of counting the number of correlations found, and when the number counted reaches the number of display characters in a line of data to be transferred, terminating the code conversion process and transferring the converted line of data to said file storage unit.

Claim 9

The method of claim 6 wherein said file storage unit comprises a track of a rotating record medium and data of a plurality of lines is stored therein in an interleaved manner such that the system data group of the first character of each of said lines are in sequence followed by the system data group of the second character of each of said lines in sequence, and so forth, said method including the process for transferring converted data to said file storage unit comprising the steps of selecting the line into which transfer is to be made by shifting the converted data into a position corresponding thereto in said data register, transferring from said file storage unit data from unselected lines into spaces between system data codes stored in said data register as a result of code conversion, and then transferring back to said file storage unit the contents of said data register.

Claim 10

The method of claim 7 wherein said file storage unit data is transferred into spaces between system data codes stored in said data register as a result of code conversion by first filling said spaces with a binary 1 in each binary digit position thereof, and then detecting groups of said digit positions in sequence, each group having a number of digit positions equal to the number of binary digits in a system code group, and substituting a system code group in said data register in place of each group of ones detected as said file storage unit is read in synchronism with recirculation of data in said data register.

Claim 11

In a CRT data display system having a cyclic display storage unit for storing at least one line of characters to be displayed and a file storage unit for storing a plurality of lines of characters, the latter storing each character in the form of a group of digital signals in a given system data code and the former storing each character in the form of a group of digital signals in a different video display code, each video code group followed by bit positions read from said display storage unit while a blank intercharacter space is being provided by said system as video code groups are cyclically read in sequence for continual regeneration of the display of said line of data, said intercharacter space bit positions being at least equal to the number of binary digits required to define a character in said systems data code, apparatus for transferring a line of data from said file storage unit to said display storage unit comprising: a first recirculating register adapted to receive said line of data from said file storage unit with adjacent system code groups separated by a sufficient number of bit positions to store a related video code group for the preceding system code group such that for a line of given number of characters to be displaced, said first recirculating register stores said given number of system data code groups so spaced as to allow a corresponding number of video display code groups to be stored therein, one video display code adjacent to its corresponding system data code group; a second recirculating register, different in length than said first recirculating register, by a number of binary digit positions equal the number of binary digit positions in a video code group plus a number of bit positions in a data code group, said second recirculating register being aDapted to store a dictionary of all system characters, each set forth in a system data code group followed by a related video display code group; comparing means connected to said first and second recirculating registers for comparing in sequence said system data code groups in said first recirculating register with system code groups for all possible characters in said second recirculating register; and means connected to said second recirculating register, said first recirculating register, and to said comparing means, for transmitting from said second register to said first register the following video code group for storage therein in a position just following its related system data code group under control of said comparator when correlation is found between a data system code group in said first recirculating register and a data system code group in said second recirculating register, whereby a line of data in said first register is converted from said system data code to said video display code for transfer to said cyclic display storage unit.

Claim 12

In a CRT data display system having a cyclic display storage unit for storing at least one line of characters to be displayed and a file storage unit for storing a plurality of lines of characters, the latter storing each character in the form of a group of digital signals in a given system data code and the former storing each character in the form of a group of digital signals in a different video display code, each video code group followed by bit positions read from said display storage unit while a blank intercharacter space is being provided by said system as video code groups are cyclically read in sequence for continual regeneration of the display of said line of data, said intercharacter space bit positions being at least equal to the number of binary digits required to define a character in said systems data code, apparatus for transferring a line of data from said file storage unit to said display storage unit comprising: a first recirculating register adapted to receive said line of data from said file storage unit with adjacent system code groups separated by a sufficient number of bit positions to store a related video code group for the preceding system code group such that for a line of given number of characters to be displaced, said first recirculating register stores said given number of system data code groups so spaced as to allow a corresponding number of video display code groups to be stored therein, one video display code adjacent to its corresponding system data code group; a second recirculating register, different in length than said first recirculating register, by a number of binary digit positions equal the number of binary digit positions in a video code group plus a number of bit positions in a data code group, said second recirculating register being aDapted to store a dictionary of all system characters, each set forth in a system data code group followed by a related video display code group; comparing means connected to said first and second recirculating registers for comparing in sequence said system data code groups in said first recirculating register with system code groups for all possible characters in said second recirculating register; and means connected to said second recirculating register, said first recirculating register, and to said comparing means, for transmitting from said second register to said first register the following video code group for storage therein in a position just following its related system data code group under control of said comparator when correlation is found between a data system code group in said first recirculating register and a data system code group in said second recirculating register, whereby a line of data in said first register is converted from said system data code to said video display code for transfer to said cyclic display storage unit.

Claim 13

Apparatus as defined in claim 9 including first means for counting each correlation found by said comparator in order to know when conversion has been completed.

Claim 14

Apparatus as defined in claim 10 including: a second means for counting the number of cycles of the longest of said first and second recirculating registers; and format error detecting means connected to said first and second counting means for determining when there have not been said given number of correlations found by said comparing means by the time the longest of said first and second registers has completed one less than a number of cycles equal to the total number of binary digit positions of storage contained therein divided by the number of binary digit positions by which it is longer than the other recirculating register.

Claim 15

Apparatus as defined in claim 11 wherein said first recirculating register is the longest.

Claim 16

Apparatus as defined in claim 11 wherein a number P of lines of data are stored in said file storage unit in an interleaved manner such that the first characters of all P lines are stored in sequence followed by the second characters of all P lines, and so forth to the last characters of all P lines, each character being set forth by a system code group, the number P being an integer which when multiplied by the number of binary digits in a system code group yields a product equal to the number of binary digit positions required to store one video code group plus said intercharacter space bit positions, and including means for transferring all P lines in interleaved order to said first register, and means for selecting the line to be converted for transfer to said display unit by shifting it into a position for comparison with the system code groups in said second register as said first and second registers are synchronously recirculated.

Claim 17

In a CRT data display system having a cyclic display storage unit for storing at least one line of characters to be displayed and a file storage unit for storing a plurality of lines of characters, the latter storing each character in the form of a group of digital signals in a given system data code and the former storing each character in the form of a group of digital signals in a given system data code and the former storing each character in the form of a group of digital signals in a different video display code, each video code group followed by bit positions read from said display storage unit while a blank intercharacter space is being provided by said system as video code groups are cyclically read in sequence for continual regeneration of the display of said line of data, said intercharacter space bit positions being at least equal to the number of binary digits required to define a character in said system data code, apparatus for transferring a line of data from said display storage unit to said file storage unit comprising: a firSt recirculating register adapted to receive a line of a given number of characters in video code from said display storage unit and to store it therein with each video code group followed by said intercharacter space bit positions; a second recirculating register, different in length than said first recirculating register by a number of binary digit positions equal to the number of binary digit positions in a video code group plus a number of binary digit positions in a system code group, said second recirculating register being adapted to store a dictionary of all system characters, each character being represented by a video code group followed by a related system code group; comparing means connected to said first and second recirculating registers for comparing in sequence said video code groups in said first recirculating register with video code groups for all possible characters in said second recirculating register; and means connected to said second recirculating register, said first recirculating register, and to said comparing means, for transmitting from said second register to said first recirculating register the following system code group for storage therein in a position just following its related video code group under control of said comparator when correlation is found between a video code group in said first recirculating register and a video code group in said second recirculating register, whereby a line of data in said second register is converted from said video display code to said system data code for transfer to said cyclic display storage unit.

Claim 18

In a CRT data display system having a cyclic display storage unit for storing at least one line of characters to be displayed and a file storage unit for storing a plurality of lines of characters, the latter storing each character in the form of a group of digital signals in a given system data code and the former storing each character in the form of a group of digital signals in a given system data code and the former storing each character in the form of a group of digital signals in a different video display code, each video code group followed by bit positions read from said display storage unit while a blank intercharacter space is being provided by said system as video code groups are cyclically read in sequence for continual regeneration of the display of said line of data, said intercharacter space bit positions being at least equal to the number of binary digits required to define a character in said system data code, apparatus for transferring a line of data from said display storage unit to said file storage unit comprising: a firSt recirculating register adapted to receive a line of a given number of characters in video code from said display storage unit and to store it therein with each video code group followed by said intercharacter space bit positions; a second recirculating register, different in length than said first recirculating register by a number of binary digit positions equal to the number of binary digit positions in a video code group plus a number of binary digit positions in a system code group, said second recirculating register being adapted to store a dictionary of all system characters, each character being represented by a video code group followed by a related system code group; comparing means connected to said first and second recirculating registers for comparing in sequence said video code groups in said first recirculating register with video code groups for all possible characters in said second recirculating register; and means connected to said second recirculating register, said first recirculating register, and to said comparing means, for transmitting from said second register to said first recirculating register the following system code group for storage therein in a position just following its related video code group under control of said comparator when correlation is found between a video code group in said first recirculating register and a video code group in said second recirculating register, whereby a line of data in said second register is converted from said video display code to said system data code for transfer to said cyclic display storage unit.

Claim 19

Apparatus as defined in claim 14 including first means for counting each correlation found by said comparator in order to know when conversion has been completed.

Claim 20

Apparatus as defined in claim 15 including: a second means for counting the number of cycles of the longest of said first and second recirculating registers; and format error detecting means connected to said first and second counting means for determining when there have not been said given number of correlations found by said comparing means by the time the longest of said first and second recirculating registers has completed one less than a number of cycles equal to the total number of binary digit positions of storage contained therein divided by the binary digit positions by which it is longer than the other recirculating register.

Claim 21

Apparatus as defined in claim 16 wherein said first recirculating register is the longest.

Claim 22

Apparatus as defined in claim 16 wherein a number P of lines of data are stored in said file storage unit in an interleaved manner such that the first characters of all lines are stored in sequence followed by the second characters of all lines, and so forth, to the last characters of all lines, each character being set represented by a system code group, the number P being an integer which when multiplied by the number of binary digits in a system code group yields a product equal to the number of bit positions required to store one video display code group plus said intercharacter space bit positions, and including means for selecting the line into which said converted data is to be transferred in said file storage unit by shifting it into a position corresponding thereto in said first register before transferring said converted data into said file storage unit.

Claim 23

Apparatus as defined in claim 18 wherein once the code conversion has been completed for a display to file transfer, the video code groups are replaced by data from said file storage unit before transferring the contents of said first recirculating register into said file storage unit, said data comprising all lines of data in said file storage unit except the line selected to receive said line of converted data.

Claim 24

Apparatus as defined in claim 19 wherein said video code groups are first replaced by like binary digits in each bit position thereof in said first register, and including means for dEtecting groups of such like binary digits in positions into which data from said file storage unit are to be transferred, and means responsive to said detecting means for effecting the transfer of said data to said positions whereby system data code groups of different lines in said file storage unit replace each of said video display code groups in said first recirculating register before data from said first recirculating register is transferred into said file storage unit.