Hitachi 7K400 Specifications - Page 172
Streaming Performance log
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UPC - 000053412935
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Error Log Index and Write Stream Error Count cleared to zero. The Write Stream Error Log is not reserved across power cycles and hardware reset. Table 116: Write Stream Error Log Description Structure Version Error Log Index Write Stream Error Log Count Reserved Write Stream Error Log Entry #1 Write Stream Error Log Entry #2 ... Write Stream Error Log Entry #31 Bytes Offset 1 00h 1 01h 2 02h 12 04h 16 10h 16 20h 16 1F0h 512 The Data Structure Version field shall contain a value of 02h indicating the second revision of the structure format. The Write Stream Error Log Count field shall contain the number of Write Stream command entries since the last power on, since this log was last read, or since a hardware reset was executed. The Error Log Index indicates the error log data structure representing the most recent error. Only values (31:0) are valid. Table 113 defines the format of each entry in the Error Log 12.20.6 Streaming Performance log Table 114 defines the format of the log returned by the Read Log Ext command, when the LBA Low register is 20h. This data set is referred to as the Streaming Performance Parameters log, the length of which (in sectors) is statically indicated in Read Log Ext log address 00h (Log Directory). The host should base its calculations on the larger of its Typical Host Interface Sector Time and the device reported Sector Time values, and on the sum of the device reported Access Time values and any additional latency that only the host is aware of (e.g. host command overhead, etc.). Table 117: Streaming Performance Parameters log Description Stream Performance Parameters log version K, Number of Regions in Sector Time Array L, Number of Positions in Position Array M, Number of Position-differences in Access Time Array Sector Time Array Position Array Access Time Array Reserved Bytes 2 2 2 2 K*8 L*8 M*4 Deskstar 7K400 Hard Disk Drive Specification 158
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