Data error detection during media write
View Patent ↗Data error detection comprises storing in a first buffer data to be written to a medium and a first digital signature of the data. If the first digital signature matches a second digital signature of data read from the first buffer, a compressed form of data read from the first buffer is stored in a FIFO. If the first digital signature matches a third digital signature of an uncompressed form of the compressed data, the uncompressed form of the compressed data, a C2 ECC of a first C1 ECC of the uncompressed form of the compressed data, and one or more C1 ECCs comprising the first C1 ECC and a second C1 ECC of the C2 ECC are stored in a second buffer. Success is indicated if the one or more C1 ECCs match corresponding C1 ECCs calculated from data and C1 ECCs read from the second buffer, and if a C1 ECC of the data read from the second buffer and written to a medium matches a C1 ECC of corresponding data read back from the medium.
1. Logic encoded in a tangible medium for execution, the logic comprising computer-readable instructions operative, when executed, to cause a processor to:
store in a first buffer data to be written to a medium and a first digital signature of said data;
if said first digital signature matches a second digital signature of the data read from said first buffer, store in a FIFO a compressed form of data read from said first buffer;
if said first digital signature matches a third digital signature of an uncompressed form of said compressed form of the data read from said first buffer, store in a second buffer:
said uncompressed form of said compressed form of the data read from said first buffer;
a C2 ECC of a first C1 ECC of said uncompressed form of said compressed form of the data read from said first buffer; and
one or more C1 ECCs, comprising said first C1 ECC and a second C1 ECC of said C2 ECC; and
if said one or more C1 ECCs match corresponding C1 ECCs calculated from data and C1 ECCs read from said second buffer, indicate a successful write if a C1 ECC of said data read from said second buffer and written to a medium matches a C1 ECC of corresponding data read back from said medium.
2. The logic of claim 1 wherein said digital signature comprises a cyclic redundancy check (CRC).
3. The logic of claim 1 wherein said digital signature comprises a checksum.
4. The logic of claim 1 wherein said digital signature comprise a hash code.
5. The logic of claim 1 wherein two or more of said first buffer, said second buffer, and said FIFO comprise separate portions of a single memory.
6. The logic of claim 1 wherein said medium comprises a serial medium.
7. The logic of claim 6 wherein said serial medium comprises a serial tape medium.
8. The logic of claim 7 wherein said serial tape medium comprises a serial magnetic tape medium.
9. The logic of claim 1 , further comprising computer-readable instructions further operative to cause the processor to indicate an error if said first digital signature does not match said second digital signature of data read from said first buffer.
10. The logic of claim 1 , further comprising computer-readable instructions further operative to cause the processor to indicate an error if said first digital signature does not match a third digital signature of said uncompressed form of said compressed form of the data read from said first buffer, or if said one or more C1 ECCs do not match said corresponding C1 ECCs calculated from said data and C1 ECCs read from said second buffer.
11. A method for data error detection, the method comprising:
storing in a first buffer data to be written to a medium and a first digital signature of said data;
if said first digital signature matches a second digital signature of the data read from said first buffer, storing in a FIFO a compressed form of the data read from said first buffer;
if said first digital signature matches a third digital signature of an uncompressed form of said compressed form of the data read from said first buffer, storing in a second buffer:
said uncompressed form of said compressed form of the data read from said first buffer;
a C2 ECC of a first C1 ECC of said uncompressed form of said compressed form of the data read from said first buffer; and
one or more C1 ECCs, comprising said first C1 ECC and a second C1 ECC of said C2 ECC; and
if said one or more C1 ECCs match corresponding C1 ECCs calculated from data and C1 ECCs read from said second buffer, indicating a successful write if a C1 ECC of said data read from said second buffer and written to a medium matches a C1 ECC of corresponding data read back from said medium.
12. The method of claim 11 wherein said digital signature comprises a cyclic redundancy check (CRC).
13. The method of claim 11 wherein said digital signature comprises a checksum.
14. The method of claim 11 wherein said digital signature comprise a hash code.
15. The method of claim 11 wherein two or more of said first buffer, said second buffer, and said FIFO comprise separate portions of a single memory.
16. The method of claim 11 wherein said medium comprises a serial medium.
17. The method of claim 16 wherein said serial medium comprises a serial tape medium.
18. The method of claim 17 wherein said serial tape medium comprises a serial magnetic tape medium.
19. The method of claim 11 , further comprising indicating an error if said first digital signature does not match said second digital signature of data read from said first buffer.
20. The method of claim 11 , further comprising indicating an error if said first digital signature does not match a third digital signature of said uncompressed form of said compressed form of the data read from said first buffer, or if said one or more C1 ECCs do not match said corresponding C1 ECCs calculated from said data and C1 ECCs read from said second buffer.