Host Interface
(6) MESSAGE REJECT message: 07h (I → T)
The message received most recently is invalid or unsupported.
(7)NO OPERATION message: 08h (I → T) This message causes no operation.
(8)MESSAGE PARITY ERROR message: 09h (I → T)
This message notifies TARG that a parity error was detected in the last message, in the last byte received by the INIT.
(9) BUS DEVICE RESET message: 0Ch (I → T)
This message instructs the clearing of all I/O operations (commands) being executed or stacked in TARG. TARG performs initialization by clearing not only I/O operations started by the INIT that sends this message but also all INIT I/O operations.
(10) IDENTIFY message:
Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
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| 1 | D | 0 | 0 | 0 |
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This message specifies the device addresses (LUN) of devices (logical units) under TARG control to establish I/O operation paths between INIT and TARG.
a. Bit 6: Disconnect Privilege
If INIT specifies this bit as 1, TARG can execute disconnection. If it specifies 0, TARG cannot execute disconnection.
b. Bits 2 to 0: LUN
These bits specify a logical unit under TARG control.
c. Message function
After the SELECTION phase, INIT first sends this message to TARG to specify the logical units to be used for I/O operation. Similarly, after the RESELECTION phase, TARG first sends this message to INIT to specify the logical units to be reconnected.
(11) SYNCHRONOUS DATA TRANSFER REQUEST message (I → T)
Byte | 0 | 1 | 2 |
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| 01h | 03h | 01h |
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| REQ/ACK Offset | |
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| Transfer Period [4 ⋅ m (ns)] | ||||
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This message defines the parameters for synchronous data transfer between two SCSI devices. Transfer Period specifies the data transfer rate. REQ/ACK Offset that can be specified for the ODD ranges from 0 to 15. If REQ/ACK Offset is 0, asynchronous transfer is used.
