Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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19.20.5 Echo Buffer Descriptor (Mode 01011b)
In this mode, a maximum of four bytes of Read Buffer Descriptor information is returned. The drive returns the descriptor
information for the echo buffer. The Buffer Offset field is reserved in this mode and must be zero. The drive transfers the lesser
of the allocation length or four bytes of following Echo Buffer Descriptor.
Table 183:Echo Buffer Descriptor
•EBOS (Echo Buffer Overwritten Supported) bit of zero indicates that the echo buffer is shared by all Initiators.
•Buffer Capacity field returns the size of the echo buffer in byte aligned to a 4-byte boundary.
Byte Bit
76543210
0 Reserved = 0 EBOS=0
1 Reserved = 0
2 Reserved = 0 (MSB) Buffer Capacity
3 Buffer Capacity (LSB)