Table 177. Initiator Request/Target Response (Dt_Req = 1, Iu_Req = 1); Table 178. Initiator Request/Target Response (Dt_Req = 1, Iu_Req = 0); Table 179. Initiator Request/Target Response (Dt_Req = 0, Iu_Req = 0) - Hitachi HUS151473VL3800 - Ultrastar 73.4 GB Hard Drive Specifications

transfer agreement and to set the protocol options between the initiator and the drive.
• Transfer Period Factor selects the transfer period and determines the timing values for the trans-
fer rate. When both DT_REQ and IU_REQ are set to one, the following values are used. For the
values larger than 9 is received from the initiator when both DT_REQ and IU_REQ are set to one,
the drive responds with these bits set to zero.
Table 177: Initiator Request/Target Response (DT_REQ = 1, IU_REQ = 1)
Initiator Request
0 <= Mi <=
9 <= Mi <=
If DT_REQ is set one and IU_REQ is set to zero, the following values are used.
Table 178: Initiator Request/Target Response (DT_REQ = 1, IU_REQ = 0)
Initiator Request
0 <= Mi <=
10 <= Mi <=
11 <= Mi <=
13 <= Mi <=
26 <= Mi <=
If both DT_REQ and IU_REQ is set to zero, the following values are used
Table 179: Initiator Request/Target Response (DT_REQ = 0, IU_REQ = 0)
Initiator Request
0 <= Mi <=
11 <= Mi <=
13 <= Mi <=
26 <= Mi <=
51 <= Mi <=
• REQ/ACK Offset determines the maximum number of REQs allowed to be outstanding before a
corresponding ACK is received at the drive during synchronous or paced transfers.
- The REQ/ACK Offset value is chosen to prevent overflow conditions in the reception buffer and offset
counter of the drive. The drive supports maximum offset of 127 (7Fh). A REQ/ACK Offset value of zero
indicates asynchronous data transfer mode and that the Transfer Period Factor and the protocol options
bits except QAS_REQ will be ignored.
• Transfer Wide Exponent defines the transfer width to be used during DATA IN and DATA OUT
phases. If any of the protocol options bits other than QAS_REQ are set to one, then only wide
transfer agreements are valid. The following values are supported.
Target
Response
8 Mt = 08h
9 Mt = 09h
Target
Response
9 Mt = 09h
10 Mt = 0Ah
12 Mt = 0Ch
25 Mt = 19h
255 Mt = 19h (Asynch Mode)
Target
Response
10 Mt = 0Ah
12 Mt = 0Ch
25 Mt = 19h
50 Mt = 32h
255 Mt = 32h (Asynch Mode)
Hitachi Ultrastar 15K147 SCSI Hard Disk Drive Specification
Target Transfer Rate
Transfer
6.25 nSec
12.5 nSec
Target Transfer Rate
Transfer
12.5 nSec
25 nSec
50 nSec
100 nSec
Target Transfer Rate
Transfer
25 nSec
50 nSec
100 nSec
200 nSec
218
Fast-160
Fast-80
Fast-80
Fast-40
Fast-20
Fast-10
Asynch
Fast-40
Fast-20
Fast-10
Fast-5
Asynch