Write Data To Echo Buffer Mode (1010B) - Seagate SCSI Interface Product Manual

218 SCSI Interface Product Manual, Rev. J
Since the downloaded microcode or control information may be sent using several commands, when the logi-
cal unit detects the last Download Microcode with Offsets and Save mode Write Buffer command has been
received, the logical unit shall perform any logical unit required verification of the complete set of downloaded
microcode or control information prior to returning Good status for the last command. After the last command
completes successfully, the logical unit shall generate a Unit Attention Condition (see Section 4.6.5) for all initi-
ators except the one that issued the set of Write Buffer commands. When reporting the Unit Attention Condi-
tion, the logical unit shall set the additional sense code to Microcode Has Been Changed.
If the complete set of Write Buffer commands required to effect a microcode or control information change (one
or more commands) are not received before a reset or power on cycle occurs, the change shall not be effective
and the microcode or control information is discarded.
The Buffer ID field identifies a specific buffer within the logical unit. The vendor assigns buffer ID codes to buff-
ers within the logical unit. A Buffer ID value of zero shall be supported. If more than one buffer is supported,
additional buffer ID codes shall be assigned contiguously, beginning with one. If an unsupported buffer ID code
is identified, the logical unit shall return Check Condition status and shall set the sense key to Illegal Request
with an additional sense code of Invalid Field in CDB.
The microcode or control information are written to the logical unit buffer starting at the location specified by the
buffer offset. The initiator shall conform to the offset boundary requirements. If the logical unit is unable to
accept the specified buffer offset, it shall return Check Condition status and it shall set the sense key to Illegal
Request with an additional sense code of Invalid Field in CDB.
The Parameter List Length specifies the maximum number of bytes that shall be transferred during the Data
Out phase to be stored in the specified buffer beginning at the buffer offset. The initiator should attempt to
ensure that the Parameter List Length plus the buffer offset does not exceed the capacity of the specified
buffer—the capacity of the buffer offset. (The initiator should attempt to ensure that the Parameter List Length
plus the Buffer Offset does not exceed the capacity field in Read Buffer descriptor.) If the Buffer Offset and
Parameter List Length fields specify a transfer that would exceed the buffer capacity, the logical unit shall return
Check Condition status and shall set the sense key to Illegal Request with an additional sense code of Invalid
Field in CDB.
5.51.7

Write Data to Echo Buffer mode (1010b)

In this mode, the target transfers data from the initiator and stores it in an echo buffer. An echo buffer is
assigned in the same manner by the target as it would for a write operation. Data shall be sent aligned on four-
byte boundaries. The Buffer ID and Buffer Offset fields are ignored in this mode.
Upon successful completion of a Write Buffer command, the data shall be preserved in the echo buffer (see
Section 5.20.4) unless there is an intervening command to any logical unit, in which case it may be changed.