Table 60 Data Format Of Hda Absolute Temperature History Table - Hitachi HDS723020BLA642 Specifications

(Queue Size+33):34 Byte[Queue Size]
511:(Queue Size Byte[512-Queue
+34) Size-34]
Note 1 – The Absolute HDA Temperature History is preserved across power cycles with the requirement
that when the drive powers up, a new entry is made in the history queue of 80h, an invalid absolute
temperature value. This way an application viewing the history can see the discontinuity in temperature
result from the drive being turned off.
Note 2 – When the Absolute HDA Temperature history is cleared, for new drives or after changing the
Logging Interval, the Queue Index shall be set to zero and the first queue location shall be set to the current
Absolute HDA Temperature value. All remaining queue locations are set to 80h.

Table 60 Data Format of HDA Absolute Temperature History Table

Queue Buffer
Reserved
Hitachi hard disk drive specifications
101
This is a circular buffer of absolute HDA
Temperature values. These are one byte 2‟s
complement numbers, which allow a range
from -127°C to +127°C to be specified. A
value of 80h indicates an initial value or a
discontinuity in temperature recording.
The Actual time between samples may vary
because commands may not be interrupted.
The sampling period is the minimum time
between samples. See Not 1.
If the host changes the logging interval using
the volatile option, the interval between
entries in the queue may change between
power cycles with no indication to the host.