Wide Data Transfer Request (01,02,03H); Initiator Request/Target Response (Scsi Ultra/Wide) - IBM DCAS-32160 - Ultrastar 2.1 GB Hard Drive Specifications

9.1.2.3 Synchronous Negotiation Started by the Initiator (SCSI Ultra/Wide)
The SCSI Ultra/Wide file responds to each Initiator requested transfer
The file responds to each Initiator requested transfer period as shown in the following figure Figure 126 on
page 168:
Initiator Target
Request Response
0 <= Mi <= 12 Mt = 12
13 <= MI <= 18 Mt = Mi
19 <= Mi <= 25 Mt = Mi
26 <= Mi <= 31 Mt = Mi
32 <= Mi <= 37 Mt = Mi
38 <= Mi <= 43 Mt = Mi
44 <= Mi <= 50 Mt = Mi
51 <= Mi <= 56 Mt = Mi
57 <= Mi <= 62 Mt = Mi
63 <= Mi <= 68 Mt = Mi
69 <= Mi <= 75 Mt = Mi
76 <= Mi <= 81 Mt = Mi
82 <= Mi <= 87 Mt = Mi
88 <= Mi <= 93 Mt = Mi
94 <= Mi <= 100 Mt = Mi
101 <= Mi <= 106 Mt = Mi
107 <= Mi <= 255 Mt = Mi
Figure 126. Initiator Request/Target Response (SCSI Ultra/Wide)

9.1.3 WIDE DATA TRANSFER REQUEST (01,02,03H)

A pair of Wide Data Transfer Request messages are exchanged between an Initiator and a Target to establish
a data transfer width agreement between the two devices. The Initiator may initiate a wide data transfer
negotiation at any time after the L U N has been identified. The Target initiates a wide data transfer negoti-
ation if the Target has not negotiated with the Initiator since the last time the Target was Reset (Power-on
Reset, SCSI Bus Hard Reset, or Bus Device Reset message).
Target-initiated negotiation occurs either immediately following the Command phase or immediately fol-
lowing the first reconnection. In either case, negotiation occurs before any Data phase between the Target
and the Initiator. The Target will negotiate the data transfer width agreement prior to negotiating the syn-
chronous data transfer agreement. If a synchronous data transfer agreement is in effect when a Wide Data
Transfer Request message is received, the Target will reset the synchronous agreement to asynchronous
mode.
The implied data transfer width agreement remains in effect until the Target is Reset (Power-on Reset, SCSI
Bus "hard" Reset, or Bus Device Reset message) or a new data transfer width agreement is negotiated. If a
Reset occurs, the Target goes to eight bit mode.
168
O E M Spec. of DCAS-34330/32160
Target
Transfer
Period
50 nSec
75 nSec
100 nSec
125 nSec
150 nSec
175 nSec
200 nSec
225 nSec
250 nSec
275 nSec
300 nSec
325 nSec
350 nSec
375 nSec
400 nSec
425 nSec
(Asynchronous mode)
Maximum
Burst
Rate
20.00 MT/s
13.00 MT/s
10.00 MT/s
8.00 MT/s
6.67 MT/s
5.71 MT/s
5.00 MT/s
4.44 MT/s
4.00 MT/s
3.64 MT/s
3.33 MT/s
3.08 MT/s
2.86 MT/s
2.67 MT/s
2.50 MT/s
2.35 MT/s
N/A