Hitachi ULTRASTAR 15K450 HUS154530VLF400 - Manual (Page 195)

Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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19.10.4 Mode Page 02 (Disconnect/Reconnect Parameters)
Table 149: Mode Page 02 (Disconnect/Reconnect Parameters)
The disconnect/reconnect page provides the Initiator with the means to tune the performance of the Fibre Channel Loop.
The drive uses the disconnect/reconnect parameters to control when it attempts to regain control of the Loop during READ
and WRITE commands.
• Read Buffer Full Ratio is the numerator of a fraction whose denominator is 256. The fraction indicates how full the
drive data buffer should be before attempting to re-arbitrate for the Loop. If the ratio is set to 0h, the target will cal-
culate and use an optimal ratio based on the negotiated transfer rate.
• Write Buffer Empty Ratio is the numerator of a fraction whose denominator is 256. The fraction indicates how empty
the drive data buffer should be before attempting to re-arbitrate for the Loop. If the ratio is set to 0h, the target will
calculate and use an optimal ratio based on the negotiated transfer rate.
Both the Read Buffer Full Ratio and the Write Buffer Empty Ratio pertain to the current active notch. For each active notch as
defined in page 0Ch there are separate Read Buffer Full Ratios and Write Buffer Empty Ratios. When the active notch is set to
zero, the values are applied in mode page 0Ch across all notches.
• Maximum Burst Size is not supported, and any value in this field is ignored.
Byte
Bit
7 6 5 4 3 2 1 0 Default
0 PS 0 Page Code = 02h 82h
1 Page Length = 0Eh 0Eh
2 Read Buffer Full Ratio 00h
3 Write Buffer Empty Ratio 00h
4-5
(MSB) Bus Inactivity Limit = 0
(LSB)
00h
6-7
(MSB) Disconnect Time Limit = 0
(LSB)
00h
8-9
(MSB) Connect Time Limit = 0
(LSB)
00h
10-11
(MSB) Maximum Burst Size
(LSB)
00h
12-15 Reserved = 0
00h