Hitachi HUS151473VL3800 - Ultrastar 73.4 GB Hard Drive Specifications page 138

• DTDC: (Data Transfer Disconnect Control) defines further restrictions for when a disconnect is permitted.
• A value of 000b indicates that DTDC is not used by the drive and disconnects are controlled by the other fields in this
page.
• A value of 001b indicates that the drive shall not attempt to disconnect when the data transfer of a command has
started until all requested data has been transferred.
• A value of 011b indicates that the drive shall not attempt to disconnect once the data transfer of a command has
started, until the command is complete.
• All other values are reserved.
•When DTDC is non-zero, the WCE bit in Mode Page 8 is ignored.
NOTE: If DTDC is nonzero and the maximum burst size is nonzero, a CHECK CONDITION status will be returned. The
sense key shall be set to ILLEGAL REQUEST and the additional sense code set to ILLEGAL FIELD IN PARAMETER LIST.
• 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). Disconnec-
tions attempted by the Target are on block boundaries only. For the case when (Maximum Burst Size x Block Size) is
less than the Block Length, the Target will transfer 1 block of data before attempting to disconnect. Value of 0000h
indicates there is no limit on the amount of data transferred per connection. Regardless of the value in Maximum
Burst Size the Target disconnects prior to completion of the data phase if the internal data buffer segment becomes
empty during a READ command or full during a WRITE command.
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.
Hitachi Ultrastar 15K147 SCSI Hard Disk Drive Specification
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