Sony SDX-800V/R User Manual

SONY AIT-3Ex drive SDX-800V series Ver.1.1 

 

6-41 

The drive supports the Disconnect-Reconnect Page which has the following format: 

PS(0) 

Reserved 

Page Code (02h) 

Page Length (0Eh) 

Buffer Full Ratio (00h) 

Buffer Empty Ratio (00h) 

(MSB) 

Bus Inactivity Limit (00h) 

 

  

(LSB) 

(MSB) 

Disconnect Time Limit (0000h) 

 

  

(LSB) 

(MSB) 

Connect Time Limit (00h) 

 

  

(LSB) 

(MSB) 

Maximum Burst Size (4000h) 

 

  

(LSB) 

Reserved 

Fair Arbitration (00b)

Reserved 

DTDC 

Reserved 

Reserved 

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 shall 

wait after releasing the SCSI bus before attempting re-selection. This should be 0 and this is non-changeable field. 

Maximum Burst Size: This field defines the maximum amount of data that the drive shall transfer during a data 

phase before disconnecting. This value is expressed in increments of 512 bytes. This is non-changeable field and 

should be 4000h. 

Note: 512 (200h) 

× 16384 (4000h) = 8388608(8 Mbytes) which means that the Maximum Burst Size is 

approximately equal to SDX-800V Buffer size for SCSI side. 

FAIR ARBITRATION: This field indicates whether the drive shall 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 shall 

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 shall 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 shall 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 shall 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.