E20425-01 •
Chapter 3 Operations
41
Error Detection and Management
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Successfully receiving a command by:
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FCP Transfer ready was sent by the command recipient
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FCP read data was received
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A response was received
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Successfully receiving write data by:
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FCP Transfer Ready was received
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A response was received
However, FCP data and FCP responses cannot always be detected.
Currently, the FCP-2 defines detection of these missing frames by using
timeouts. For FCP responses, the target may request the initiator to send an
FCP confirmation to confirm receipt of the response. Refer to FCP-2 for a
more detailed description.
Caution:
From a tape drive standpoint, it is very important that error
detection and recovery ensure both the initiator and target are in
sync with block position on tape. Therefore; if the initiator suspects
that the result of an error leaves the drive out of sync with the
initiator, the initiator should issue a Read Position command to
determine the location and to invoke the Upper Level Protocol
(FC-4) to reposition the tape if necessary.
Fibre Channel provides no error correction on data during transfers but it does
provide excellent error detection schemes, including:
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8B/10B encoding and decoding
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Disparity
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Cyclic redundancy checks
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Sequence errors and out-of-order delivery
8B/10B Encoding and Decoding
Fibre Channel uses a special process called encoding and decoding that is
designed to reduce distortion during transmission and aid in the detection of
errors at the receiving port. This process makes it highly likely that single and
multiple bit errors are detected.
Besides providing error detection, this process also balances the turning on
and off of the light for the loading of the optical fiber transmitters.
The process of encoding uses an algorithm that takes the original 8 bits in
each byte and transforms them into 10 bits for transmission. The result is an
8B/10B encoding of a byte and is called a transmission character.
Summary of Contents for Storage Tek T10000
Page 14: ...Tables xiv T10000 Interface Reference Manual January 2011 E20425 01...
Page 18: ...What s New xx T10000 Interface Reference Manual January 2011 E20425 01...
Page 82: ...Private Loop SCSI Target Discovery 64 T10000 Interface Reference Manual January 2011 E20425 01...
Page 286: ...Glossary 268 T10000 Interface Reference Manual January 2011 E20425 01...
