Table of Contents
Parallel Protocol Request
7
0
1
2
3
4
5
6
7
PComp_En
Fields:
Transfer Period
Factor
Req/Ack Offset
Transfer Width
Exponent
PComp_En
RTI
Rd_Strm
Wr_Flow
Hold_MCS
QAS_Req
DT_Req
IU-Req
Status
A Status byte is sent from the drive to the host during the Status phase at the end of each
command as specified in the SCSI specification, unless the command has been cleared by an
message, by a
ABORT
26
Messages
6
5
Extended Message (01h)
Extended Message Length (06h)
Parallel Protocol Request (04h)
Transfer Period Factor
Req/Ack Offset
Transfer Width Exponent
RTI
Rd_Strm WR_Flow Hold_MCS QAS_Req DT_Req IU_Req
08h
Transfer period of 6.25 ns, Paced Information Unit transfers
Transfer period of 12.5 ns (FAST-80). Only valid when DT transfers have
09h
been requested
0Ch
Transfer period of 50 ns (FAST-20) — LVD/SE drives only
19h
Transfer period of 100 ns (FAST-10)
Transfer period of 200 ns (FAST-5)
32h
This has a maximum value of 255.
For ST transfers, this can be either 0 (Narrow) or 1 (Wide).
For DT transfers, it must be set to 1.
Precompensation enable bit. Supported.
Retain Training Information bit. Supported.
0
Read streaming and read flow control enable bit. Not supported, so the
drive will always return zero.
0
Write flow control enable bit. Not supported; the drive will always return
zero.
0
Hold Margin Control Settings bit. Not supported; the drive will always return
zero.
0
QAS enable request bit. Not supported; the drive will always return zero.
This bit determines whether DT mode has been requested, in other words,
packetized data transfers. Supported.
Information units enabled request bit. Supported.
message, or by a hard reset.
BUS DEVICE RESET
4
3
Reserved (0)
2
1
0
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