Sync pattern encoding system for run-length limited codes

Claim 3

The method set forth in claim 1 in which said run-length limited code is a fixed rate code.

Claim 4

The method set forth in claim 1 in which said run-length limited code is a variable word length code.

Claim 5

The method set forth in claim 1 in which said run-length limited code is a fixed rate, variable word length code.

Claim 6

The method set forth in claim 4 in which the run-lengths of said code are 2,7.

Claim 7

The method set forth in claim 5 in which said special signal pattern is adapted to be recorded on a magnetic disk.

Claim 8

The method set forth in claim 5 further including the step of recording said second and forth signals sequentially onto a track for a magnetic data storage unit to provide a signal for use in synchronizing another device with said unit prior to recording data from said storage unit.

Claim 9

The method set forth in claim 6 in which said predefined sequence is 100, said code word is defined in said dictionary as 100100 and said data word is defined in said dictionary as 010.

Claim 10

The method set forth in claim 8 in which the data word code word dictionary consists of the following words: ______________________________________ Data Word Code Word ______________________________________ 10 0100 010 100100 0010 00100100 11 1000 011 001000 0011 00001000 000 000100 ______________________________________

Claim 13

The method set forth in claim 10 in which said run-length limited code has a fixed rate and variable word lengths.

Claim 14

The method set forth in claim 11 in which said data is at least one group of serial adjacent bits is 010.

Claim 15

The method set forth in claim 12 in which said preselected data character is defined by the binary bit pattern of 010010XX, when X can be a binary 1 or binary 0.

Claim 16

The method set forth in claim 13 further including the step of recording the output signal from said encoder onto said disk file in order to read said recorded output signal prior to transfer of data from said file to another unit.

Claim 17

The method set forth in claim 14 in which the bit pattern of the encoded output signal is 100100.

Claim 18

The method set forth in claim 15 in which said dictionary comprises the following data word, code word definitions: ______________________________________ Data Word Code Word ______________________________________ 10 0100 010 100100 0010 00100100 11 1000 011 001000 0011 00001000 000 000100 ______________________________________

Claim 19

In a system for recording data on a disk file wherein binary signals representing characters of data are presented to a run-length limited serial encoder which provides a coded serial by bit output signal representing corresponding characters, said encoder being connected to said file so said output signal is recorded on said disk file in the form of magnetic transitions, and a serial run-length decoder connected to said file for reading said transitions from said file and providing a decoded output signal; a system for selectively recording a sync pattern on said file having the highest frequency permitted by the constraint said run-length limited code which limits the number of binary zeros between adjacent binary ones, said system including means also connecting the output of said encoder selectively to said decoder and the output of said decoder selectively to the input of said encoder whereby once that an initial portion of said sync pattern is encoded, the remaining portion of said sync pattern is supplied to said disk file without supplying signals to the input of said encoder from a source external to said recording system.

Claim 20

In a system for recording data on a disk file wherein binary signals representing characters of data are presented to a run-length limited serial encoder which provides a coded serial by bit output signal representing corresponding characters, said encoder being connected to said file so said output signal is recorded on said disk file in the form of magnetic transitions, and a serial run-length decoder connected to said file for reading said transitions from said file and providing a decoded output signal; a system for selectively recording a sync pattern on said file having the highest frequency permitted by the constraint said run-length limited code which limits the number of binary zeros between adjacent binary ones, said system including means also connecting the output of said encoder selectively to said decoder and the output of said decoder selectively to the input of said encoder whereby once that an initial portion of said sync pattern is encoded, the remaining portion of said sync pattern is supplied to said disk file without supplying signals to the input of said encoder from a source external to said recording system.

Claim 21

The combination recited in claim 17 further including means for initially supplying to said encoder a bit pattern which is encoded into said initial portion of said sync pattern.

Claim 22

The combination recited in claim 18 in which said run-length limited code is a fixed rate, variable word length code.

Claim 23

The combination recited in claim 18 in which said bit pattern which is encoded into said initial portion is 010.

Claim 24

The combination recited in claim 19 in which said constraint is two 0's and said sync pattern comprises a sequence of groups, each group having a 100 bit pattern.

Claim 25

The combination recited in claim 18 in which said encoder and decoder operate on a run-length limited code defined by the following data word, code word dictionary: ______________________________________ Data Word Code Word ______________________________________ 10 0100 010 100100 0010 00100100 11 1000 011 001000 0011 00001000 000 000100 ______________________________________

Claim 26

A recorded channel for a disk file adapted to be connected between a source of data to be stored on said file and the magnetic transducer of said file, said channel including means connected to said source of data for receiving a plurality of binary signals in parallel representing one character, means for converting said parallel signals to a serial stream of binary bit signals corresponding to said character, an encoder connected to said connecting means for encoding said serial stream into an encoded serial stream wherein adjacent 1 bits are always separated by at least two binary zeros and there are never more than seven continuous binary 0 bits, means connecting the output of said encoder to supply said encoded stream to said magnetic transducer, a decoder connected to said transducer adapted to receive encoded data signals from said file and provide a decoded output signal, means selectively connecting the output of said encoder to the input of said decoder to also provide a decoder output signal corresponding to said input signal to said encoder, means for selectively connecting the output of said decoder to the input of said encoder, and control means connected to both said means for selectively connecting and operable to cause said encoder and decoder to be connected in a continuous signal loop whereby said encoder provides a predefined repetitive pattern of binary bits to said disk file in response to operation of said control means.

Claim 27

A recorded channel for a disk file adapted to be connected between a source of data to be stored on said file and the magnetic transducer of said file, said channel including means connected to said source of data for receiving a plurality of binary signals in parallel representing one character, means for converting said parallel signals to a serial stream of binary bit signals corresponding to said character, an encoder connected to said connecting means for encoding said serial stream into an encoded serial stream wherein adjacent 1 bits are always separated by at least two binary zeros and there are never more than seven continuous binary 0 bits, means connecting the output of said encoder to supply said encoded stream to said magnetic transducer, a decoder connected to said transducer adapted to receive encoded data signals from said file and provide a decoded output signal, means selectively connecting the output of said encoder to the input of said decoder to also provide a decoder output signal corresponding to said input signal to said encoder, means for selectively connecting the output of said decoder to the input of said encoder, and control means connected to both said means for selectively connecting and operable to cause said encoder and decoder to be connected in a continuous signal loop whereby said encoder provides a predefined repetitive pattern of binary bits to said disk file in response to operation of said control means.

Claim 28

The combination recited in claim 23 further including means for selectively connecting said converting means to said encoder, and means for connecting said control means to said further means operable to cause said further means to disconnect said converter from said encoder when the output of said decoder is connected to the input of said encoder.

Claim 29

The combination recited in claim 24 in which said one character is defined as 010010XX where X is either a binary 1 or a binary 0.

Claim 30

The combination recited in claim 25 in which said encoded serial stream consists of a sequence of groups of binary bits each group comprising a 100 bit pattern.

Claim 31

The combination recited in claim 26 in which said encoder and decoder operate on a run-length limited code defined by the following data word, code word dictionary: ______________________________________ Data Word Code Word ______________________________________ 10 0100 010 100100 0010 00100100 11 1000 011 001000 0011 00001000 000 000100 ______________________________________