Error correction code dynamic range control system
First Claim
1. In an electronic data storage device controller for reading a plurality of sectors from a data storage device, each of said sectors having a pre-data field, a data field, and a redundancy field, and wherein said device controller provides correction information for said pre-data field, said data field, and said redundancy field, dynamic range control apparatus for indicating which of said correction information is only for said data field, said apparatus comprising:
- means for determining a count of a number of bytes in each of said fields, said means providing a pre-data count, a data count, and a redundancy count;
counter means, responsive to a byte count signal, for decrementing each of said counts;
range indicator means responsive to said counter means for indicating which of said correction information is only for said data field, wherein correction of said pre-data field and said redundancy field is prevented.
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Accused Products
Abstract
Disclosed is a dynamic range control circuit for determining when to allow an error correction circuit to correct data read from a sector of a disk data storage device. The circuit has two sets of registers used to count bytes of information within a sector. A first set of registers counts bytes as the sector is being read from the disk, and accumulates a count of a pre-data field and a count of a data field. These counts are then loaded into a second set of registers, along with a count indicating the length of the redundancy field within the sector. As correction is being performed, the second set of registers is decremented and the values in the registers used to set an in-range signal which allows a correction to the data field and prevents correction to the pre-data or redundancy fields.
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Citations
12 Claims
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1. In an electronic data storage device controller for reading a plurality of sectors from a data storage device, each of said sectors having a pre-data field, a data field, and a redundancy field, and wherein said device controller provides correction information for said pre-data field, said data field, and said redundancy field, dynamic range control apparatus for indicating which of said correction information is only for said data field, said apparatus comprising:
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means for determining a count of a number of bytes in each of said fields, said means providing a pre-data count, a data count, and a redundancy count; counter means, responsive to a byte count signal, for decrementing each of said counts; range indicator means responsive to said counter means for indicating which of said correction information is only for said data field, wherein correction of said pre-data field and said redundancy field is prevented. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In an electronic data storage device controller for reading a plurality of sectors from a data storage device, each of said sectors having a pre-data field, a data field, and a redundancy field, and wherein said device controller provides correction information for said pre-data field, said data field, and said redundancy field, dynamic range control apparatus for indicating which of said correction information is only for said data field, said apparatus comprising:
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pre-data count means for determining a count of a number of bytes in said pre-data field; data count means for determining a count of a number of bytes in said data field; redundancy count means for determining a count of a number of bytes in said redundancy field; first counter means for decrementing said redundancy count means each time a byte count signal is received; redundancy underflow means for indicating a redundancy underflow when said first counter means decrements to zero; second counter means for decrementing said data count means each time a byte count signal is received after said redundancy underflow is indicated; data underflow means for indicating a data underflow when said second counter means decrements to zero; third counter means for decrementing said pre-data count means each time a byte count signal is received after said data underflow is indicated; and range control means responsive to said redundancy underflow and said data underflow for indicating which of said correction information is only for said data field, wherein correction of said pre-data field and said redundancy field is prevented. - View Dependent Claims (8, 9, 10)
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11. In an electronic data storage device controller having means for reading a plurality of sectors from a data storage device, each of said sectors having a pre-data field, a data field, and a redundancy field, and wherein said device controller provides correction information for said pre-data field, said data field, and said redundancy field, a process for providing an indication that said correction information is only for said data field, said process comprising:
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(a) determining a count of a number of bytes in said pre-data field and transferring said count to a pre-data counter; (b) determining a count of a number of bytes in said data field and transferring said count to a data counter; (c) determining a count of a number of bytes in said redundancy field and transferring said count to a redundancy counter; (d) decrementing said redundancy counter each time a byte count signal is received; (e) decrementing said data counter each time a byte count signal is received and said redundancy counter is zero; (f) decrementing said pre-data counter each time a byte count signal is received and said data counter is zero; and (g) indicating that said correction information is only for said data field when said redundancy counter is zero and said data counter is non-zero, wherein correction of said pre-data field and said redundancy field is prevented. - View Dependent Claims (12)
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Specification