Sun Oracle Storage Tek T10000, Справочное руководство

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Read Command
150 T10000: Interface Reference Manual • January 2011 • E20425-01
Data Integrity Validation—Read Operations
During read operations when DIV mode is enabled, all Read commands
should have a transfer length that includes both the user data and the
appended 4 bytes of Protection Information.
Note: Use the Mode Select command Page 0Ah, Subpage F0h, to enable the
DIV mode.
When in DIV mode the T10000 A and B tape drives generate the PI data as it
is being transferred from the tape drive to the controller data buffer.
On T10000C tape Drives the PI data is read from the media and transferred to
the controller data buffer.
If an error occurs during Read operations, and the drive detects a
miscompare, it reports it as a:
Check condition, with

Key = 04h (Hardware Error), and

ASC/ASCQ = 10 01h — Logical Block Guard Check Failed
Examples of when this may occur include:
• During the transfer of data from the tape drive to the controller data buffer,
PI data is generated or checked as required.
• During the transfer of data from the controller data buffer to the Fibre
Channel Port protocol chip, if it supports the current PI method.
• If the transfer length is more than the actual user data plus the PI bytes the
tape drive returns all available user data and the PI bytes, reporting an
Illegal Length Indicator (ILI).
• If the transfer length is less than the actual user data plus the PI bytes the
tape drive checks the entire record in the controller data buffer against the
PI bytes. Then reports a PI miscompare if necessary.
If there is no PI error then only the requested number of data bytes are
returned to the Host, reporting of ILI and residuals as usual.