Table 2.11 Valid Protocol Options Bit Combinations - Fujitsu MBA3073 SERIES Technical Manual

A DT enable request bit (DT_REQ) of zero indicates that DT DATA phases are to be disabled
when received from the originating SCSI device and that DT DATA phases are not supported
when received from the responding SCSI device. An DT_REQ bit of one indicates that DT
DATA phases are to be enabled when received from the originating SCSI device and that DT
DATA phases are supported when received from the responding SCSI device.
A QAS enable request bit (QAS_REQ) of zero indicates that QAS is to be disabled when received
from the originating SCSI device and that QAS is not supported when received from the
responding SCSI device.
The INIT shall set HOLD_MCS to one to indicate that the TARG should hold any margin control
settings set with the MARGIN CONTROL SUBPAGE of the PORT CONTROL MODE PAGE
(see LOGICAL SPECIFICATION). In response, the TARG shall set HOLD_MCS to one if it is
capable of retaining the settings and zero if it is not.
When the INIT shall set HOLD_MCS to zero to indicate that the TARG should reset this mode
page.
Not all combinations of the protocol options bits are valid. Only the bit combinations defined in
table 2.11 shall be allowed all allowed. All other combinations are reserved.
PCMP_EN RTI RD_STRM WR_FLOW HOLD_MCS QAS_REQ
0 0
0 0
0 0
1 0/1 0/1
1 0/1 0/1
A PARALLEL PROTOCOL REQUEST agreement applies to all logical units of the two SCSI
devices that negotiated agreement. That is, if SCSI device A, acting as an INIT negotiates a data
transfer agreement with SCSI device B (a TARG), then the same data transfer agreement applies
to SCSI devices A and B even if SCSI device B changes to an INIT.
A data transfer agreement only applies to the two SCSI devices that negotiate the agreement.
Separate data transfer agreements are negotiated for each pair of SCSI devices. The data transfer
agreement only applies to DATA phases and information unit transfers.
C141-C015
Table 2.11 Valid protocol options bit combinations
0 0 0/1
0 0 0/1
0 0 0/1
0/1 0/1
0/1 0/1
DT_REQ IU_REQ
0 0 0
1 0 0
1 1 0
1 0 1
1 1 1
DESCRIPTION
Use ST DATA IN and ST
DATA OUT phases to
transfer data
Use ST DATA IN and ST
DATA OUT phases to
transfer data with
asynchronous transfers, and
participate in QAS
arbitrations.
Use DT DATA IN and DT
DATA OUT phases with
data group transfers and
QAS arbitration.
Use DT DATA IN and DT
DATA OUT phases with
information unit transfer.
Use DT DATA IN and DT
DATA OUT phases with
information unit transfer.
And QAS arbitration.
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