Parallel Protocol Request
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| 7 | 6 | 5 |
| 4 | 3 |
| 2 | 1 | 0 |
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| Extended Message (01h) |
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| Extended Message Length (06h) |
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| Parallel Protocol Request (04h) |
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| 3 |
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| Transfer Period Factor |
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| 4 |
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| Reserved (0) |
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| 5 |
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| Req/Ack Offset |
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| Transfer Width Exponent |
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| 7 | PComp_En | RTI | Rd_Strm |
| WR_Flow | Hold_MCS |
| QAS_Req | DT_Req | IU_Req |
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Fields:
Transfer Period | 08h | Transfer period of 6.25 ns, Paced Information Unit transfers |
Factor | 09h | Transfer period of 12.5 ns |
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| been requested |
| 0Ch | Transfer period of 50 ns |
| 19h | Transfer period of 100 ns |
| 32h | Transfer period of 200 ns |
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Req/Ack Offset | This has a maximum value of 255. | |
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Transfer Width | For ST transfers, this can be either 0 (Narrow) or 1 (Wide). | |
Exponent | For DT transfers, it must be set to 1. | |
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PComp_En | Precompensation enable bit. Supported. | |
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RTI | Retain Training Information bit. Supported. | |
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Rd_Strm | 0 | Read streaming and read flow control enable bit. Not supported, so the |
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| drive will always return zero. |
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Wr_Flow | 0 | Write flow control enable bit. Not supported; the drive will always return |
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| zero. |
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Hold_MCS | 0 | Hold Margin Control Settings bit. Not supported; the drive will always return |
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| zero. |
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QAS_Req | 0 | QAS enable request bit. Not supported; the drive will always return zero. |
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DT_Req | This bit determines whether DT mode has been requested, in other words, | |
| packetized data transfers. Supported. | |
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Information units enabled request bit. Supported. | ||
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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 ABORT message, by a BUS DEVICE RESET message, or by a hard reset.
26 Messages