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6.Command Specification MODE SELECT
6-44 SONY AIT-5 drive SDX-1100V series Ver.1.0
6.7.1. Disconnect-Reconnect Page (02h)
The drive supports the Disconnect-Reconnect Page which has the following format:
Table 6-43: Disconnect-Reconnect Page
Bit
Byte
7 6 5 4 3 2 1 0
0 PS(0) Reserved Page Code (02h)
1 Page Length (0Eh)
2 Buffer Full Ratio (00h)
3 Buffer Empty Ratio (00h)
4 (MSB) Bus Inactivity Limit (00h)
5 (LSB)
6 (MSB) Disconnect Time Limit (0000h)
7 (LSB)
8 (MSB) Connect Time Limit (00h)
9 (LSB)
10 (MSB) Maximum Burst Size (4000h)
11 (LSB)
12 Reserved Fair Arbitration (00b)
Reserved DTDC
13 Reserved
14 Reserved
15 Reserved
Buffer Full Ratio, Buffer Empty Ratio, Bus Inactivity Limit and Connect Time Limit fields are not supported by the
drive if set to non-ZERO values a CHECK CONDITION status is returned with ILLEGAL REQUEST sense key
set.
Disconnect Time Limit: This field indicates the minimum time in 100 microsecond increments that the drive will
wait after releasing the SCSI bus before attempting re-selection. This will be 0 and this is non-changeable field.
Maximum Burst Size: This field defines the maximum amount of data that the drive will transfer during a data
phase before disconnecting. This value is expressed in increments of 512 bytes. This is non-changeable field and
will be 4000h.
Note: 512 (200h) × 16384 (4000h) = 8388608(8 Mbytes) which means that the Maximum Burst Size is
approximately equal to SDX-1100V Buffer size for SCSI side.
FAIR ARBITRATION: This field indicates whether the drive will use fair or unfair arbitration when requesting an
interconnect tenancy. Setting this field to 1 will enable the SCSI Bus Fairness protocol. Setting this field to zero will
disable it. The drive determines fairness by monitoring prior arbitration attempts by other SCSI devices. It will
postpone arbitration for itself until all lower priority SCSI devices that previously lost arbitration either win a
subsequent arbitration or discontinue their arbitration attempts. It will monitor the arbitration attempts of the other
SCSI devices and refresh the fairness register with the SCSI ID’s of any lower priority SCSI devices that lost
arbitration. This field is not support.
DTDC: This field defines further restrictions on when a disconnect is permitted.
DTDC Description
00b
01b
10b
11b
Data transfer disconnect control is not used. Disconnect is controlled by the other field in this
page.
A target will not attempt to disconnect once the data transfer of a command has started until all
data the command is to transfer has been transferred. The connect time limit and bus inactivity
limit are ignored during the data transfer.
Reserved
A target will not attempt to disconnect once the data transfer of a command has started until
the command is complete. The connect time limit and bus inactivity limit are ignored once data
transfer has started.