6.Command Specification
READ BUFFER
SONY AIT-5 drive SDX-1100V series Ver.1.0
6-72
Echo Buffer (1010b) -
In this mode the drive transfer data to the application client from the echo buffer. The echo
buffer will 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 READ BUFFER
command will return the same number of bytes of data as received in the prior echo buffer mode WRITE BUFFER
command from the same initiator.
The initiator may send a READ BUFFER command requesting the echo buffer descriptor prior to a WRITE
BUFFER command. If an echo buffer mode WRITE BUFFER command is successful then the initiator may send
multiple echo buffer mode READ BUFFER commands to read the echo buffer data multiple times.
Echo buffer descriptor (1011b) -
In this mode, a maximum of four bytes of READ BUFFER descriptor information
is returned. The drive will return the descriptor information for the echo buffer. The BUFFER OFFSET field is
reserved in this mode. The allocation length will be set to four or greater.
Table 6-76: Echo Buffer descriptor
Bit
Byte
7 6 5 4 3 2 1 0
0
Reserved EBOS
(1)
1
Reserved
2
Reserved (MSB)
3
BUFFER CAPACITY
(LSB)
The BUFFER CAPACITY field will return the size of the echo buffer in bytes aligned to a four-byte boundary. The
maximum echo buffer size is 4096 bytes.
