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US 4,380,029 AGranted
Data recording format and method and apparatus for producing same
AssigneeBTI Computer Systems
InventorElwood J. Bode
Life of this patent
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AssigneeBTI Computer Systems
InventorElwood J. Bode
Estimating the term…
A sector of data to be recorded on a magnetic medium is formatted by dividing the data sector into a plurality of data segments. Recorded with each segment is a time code which is identical for all segments in a given sector. During recordation of the data and time code for each segment, a cyclic redundancy check (CRC) signal is generated and the CRC signal is recorded after the data and the time code. As data in a segment is recorded, it is also temporarily stored. The temporarily stored data is combined according to a prescribed function with data in the succeeding segment and that function is temporarily stored for combination with the data in the next succeeding segment so that after all segments of data have been recorded there is a function that uniquely represents the data in all data segments. The function is recorded as a check segment. On recovery of the data, an error in any given segment can be detected by employment of the CRC signal associated with the segment containing an error. Reconstruction of the data in the erroneously recorded or read segment can be achieved by combining the contents of the correctly recorded and read data segments and the check segment, provided that the time codes read in these segments are identical.
Apparatus for recording data in the form of a sector of serially occurring binary bits onto a storage medium comprising means for sequentially grouping the bits into n data segments wherein n is a positive integer greater than one and each data segment includes 1/n times the number of bits in said sector, means coupled to said grouping means for transmitting the bits in a data segment to said storage medium, means coupled to said grouping means for temporarily storing a data segment of bits, means coupled to said grouping means and said storing means for combining in accordance with a prescribed function the bits of the data segment in said storing means with the bits in the immediately succeeding data segment thereby to update the contents of said storing means as each data segment is transmitted to said storage medium, means responsive to the bits in a data segment for generating a CRC signal, means for coupling the CRC signal to said transmitting means so that the CRC signal is applied to the storage medium in association with the data segment in response to which the CRC signal is generated, and means for transmitting the content of said storing means to said storage medium for storage thereinafter the nth data segment and the CRC signal associated therewith, thereby to establish a check segment containing a data pattern representative of the data stored in all said data segments.
A method for storing a sector of serially occurring data bits onto a storage medium comprising the steps of recording onto the medium a first segment of data, the first segment having 1/n times the number of bits in the sector, wherein n is a positive integer greater than one, deriving a first CRC signal from the data in the first segment during recording thereof, then writing said first CRC signal onto the medium after said first segment, temporarily storing the data in the first segment, then recording a second segment of data onto the medium, said second segment having 1/n bits, deriving a second CRC signal from the data in the second segment during recording thereof, then writing said second CRC signal onto the medium after said second segment, combining the data in the second segment with the temporarily stored data from the first segment in accordance with a prescribed function to form a data block uniquely representative of the combination of the data in all segments previously recorded, temporarily storing the data block, repeating said recording, deriving, writing, storing and combining steps for all segments from the third segment to the nth segment, the final combining step producing a combined data block, and then recording the combined data block onto the medium as a check segment after the nth segment.
A method for storing a sector of data on a magnetic medium comprising the step of serially dividing the sector into a plurality of segments wherein each segment contains less data than the sector, recording each segment on the magnetic medium, recording after each segment a time code indicative of the time of recording the sector, generating from the data in the segment and the time code associated with the data a CRC signal having a value representative of the data and the time code, temporarily storing the data in each segment as it is recorded, generating from temporarily stored data a data block that is a prescribed function of the temporarily stored data and the data in all previously recorded data segments, and recording the data block as a check segment after all data segments have been recorded so as to afford reconstruction of the data in one data segment from the data in the other data segments and the check segment.
Dependencies are inferred from the claim text.