Fujitsu MAN3735 Manuale Utente
C141-E124-01EN
3 - 128
(5)
Mode = 1, 0, 1, 0 : Echo buffer
In this mode the IDD transfers data to the INIT from the echo buffer. The echo buffer shall transfer
the same data as when the WRITE BUFFER command with the mode field set to echo buffer was
issued. The BUFFER ID and BUFFER OFFSET fields are ignored in this mode.
the same data as when the WRITE BUFFER command with the mode field set to echo buffer was
issued. The BUFFER ID and BUFFER OFFSET fields are ignored in this mode.
(6)
Mode = 1, 0, 1, 1 : Echo buffer descriptor
In this mode, a maximum of four bytes of READ BUFFER descriptor information is returned. The
device server shall return the descriptor information for the echo buffer. The "Buffer Offset" field
is reserved in this mode. The allocation length should be set to four or greater. The device server
shall transfer the lesser of the allocation length or four bytes of READ BUFFER descriptor. The
READ BUFFER descriptor is defined as shown in Figure 3.27.
device server shall return the descriptor information for the echo buffer. The "Buffer Offset" field
is reserved in this mode. The allocation length should be set to four or greater. The device server
shall transfer the lesser of the allocation length or four bytes of READ BUFFER descriptor. The
READ BUFFER descriptor is defined as shown in Figure 3.27.
Bit
Byte
Byte
7
6
5
4
3
2
1
0
0
Reserved
EBOS
1
Reserved
2
Reserved
Echo Butffer Capacity (MSB)
3
Echo Buffer Capacity (LSB)
Figure 3.27 READ BUFFER command: Echo buffer descriptor
The IDD return one in EBOS field, and the IDD verifies that echo buffer data from each initiator is the
same as that previously written by the same initiator.
same as that previously written by the same initiator.
The "Buffer Capacity" field returns the size of the echo buffer X'0200' in bytes aligned to a four-byte
boundary.
boundary.