Fujitsu MBA3147RC Manuale Utente

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CHAPTER 6  Sense Data and Error Recovery 
Methods 
6.1 
Sense Data 
6.2 
INIT Error Recovery Methods (Recommended) 
6.3 
Disk Drive Error Recovery Processing 
 
In this chapter, the configuration and contents of sense data reported to the INIT 
(initiator) when an error occurs, etc., key information for interpreting error states, 
recommended procedures for error recovery processing that should be executed 
by software in the INIT and error recovery processing executed internally by the 
HDD are described. 
6.1   Sense Data 
When the HDD reports a CHECK CONDITION status, or in cases when some fatal 
error is detected in connection with the SAS interface, and as a result, the command 
that is currently being executed, or the commands in the stack are cleared, it generates 
sense data for the INIT that issued that command.  Sense data are returned to the 
INIT at the same time as the status is sent in response to the command. 
6.1.1  Sense data format 
The HDD's sense data is in the so-called "Expanded Sense Data" format.  The 
expanded sense data format supported by the HDD is shown in Table 6.1. 
 
1)  In the specifications, each device is permitted to define 
whatever it chooses after byte 18 of the expanded sense data, 
and the length and format differ for each device. The length of 
expanded sense data is displayed in the sense data, so by 
analyzing the sense data which it receives, the INIT can know 
its effective length.