User's Guide

64 SCSI Commands

Therefore the value contained in the Buffer Offset field of subsequent READ BUFFER commands should

be a multiple of 2

offset boundary

as shown in the following table.

Buffer Capacity – This field returns the size of the requested buffer in bytes.

The Return Buffer stops being filled when the number of allocation length bytes has been transferred or

when all the available data from the buffer has been transferred, whichever amount is less. This holds true

for either mode.

In Echo Buffer Descriptor Mode, an echo buffer descriptor is returned as shown in the following table.

Echo Buffer Overwritten Supported (EBOS) – This field returns a 0 to indicate that other initiators or

intervening commands may overwrite the echo buffer.

Buffer Capacity – This field returns 252, which is the size of the echo buffer (in bytes).

Table 62 Offset Boundary

Offset Boundary 2

offset boundary

Buffer Offsets

0h 2

= 1 Byte boundaries

1h 2

= 2 Even-byte boundaries

2h 2

= 4 Four-byte boundaries

3h 2

= 8 Eight-byte boundaries

4h 2

= 16 16-byte boundaries

::Etc.

FFh Not applicable 0 is the only supported buffer offset

Table 63 Echo Buffer Descriptor

Bit

Byte

76543210

0 Reserved EBOS

1 Reserved

2 Reserved MSB

Buffer Capacity

LSB