IBM Ultrastar 36LZX, Технические характеристики

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8.8.4Mode Page 2 (Disconnect/Reconnect Parameters)
00h
00h
00h
Reserved = 0 13-15
00h DTDC RSVD DIMM Fair arbitration 12
00h
00h (MSB) Maximum Burst Size
(LSB)
10-11
00h
00h (MSB) Connect Time Limit = 0
(LSB)
8-9
00h
00h (MSB) Disconnect Time Limit = 0
(LSB)
6-7
00h
00h (MSB) Bus Inactivity Limit = 0
(LSB)
4-5
00h Write Buffer Empty Ratio 3
00h Read Buffer Full Ratio 2
0Eh Page Length = 0Eh 1
82h Page Code = 02h RSVD=0 PS 0
0 1 2 3 4 5 6 7
Default
Bit
Byte
Figure 84. Mode Page 2 (Disconnect/Reconnect Parameters )
The disconnect/reconnect page provides the initiator with the means to tune the performance of the
SCSI bus.
An initiator may use the IDENTIFY message to grant the drive the general privilege of disconnecting.
(Disconnect requests may still be selectively rejected by the initiator by issuing a MESSAGE REJECT).
The drive uses the disconnect/reconnect parameters to control reconnection during READ (operation
code 08h and 28h) and WRITE ( 0Ah, 2Ah and 2E).
Ÿ
Read Buffer Full Ratio is the numerator of a fraction whose denominator is 256. The fraction indi-
cates how full the drive data buffer should be before attempting to reconnect to the SCSI bus. If the
ratio is set to 0h, the target will calculate and use an optimal ratio based on the negotiated transfer
rate.
Ÿ
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 reconnect to the SCSI bus.
If the ratio is set to 0h, the target will calculate and use an optimal ratio based on the negotiated
transfer rate.
Ÿ
Maximum Burst Size is the maximum amount of data that the Target transfers during a data phase
before disconnecting if the Initiator has granted the disconnect privilege. This value is expressed in
increments of single block size (for example, a value of 0001h means 512 bytes, 0002h means 1024
bytes when the block size is 512 bytes). Disconnections attempted by the Target are on block bound-
aries only. For the case when (Maximum Burst Size x Block Size) is less than the Block Length, the
Ultrastar 36LZX hard disk drive specifications
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