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TAPE UNIT SCSI COMMANDS M2488 PRODUCT GUIDE
4-148 CG00000-011503 REV. A April 1997
NOTES:
1. Since an automatic reset is performed upon completing the Write Buffer command in Down-
load Microcode With Offsets mode, the MICROCODE HAS BEEN CHANGED unit attention
condition is replaced with the POWER ON/RESET unit attention condition.
2. The microcode image that is downloaded via the WRITE BUFFER command includes the con-
troller and servo microcode. In the Download Microcode With Offsets mode, only the control-
ler microcode is copied to control store and activated. The downloaded servo microcode is not
used and the previous servo code remains active. In order to change the servo code, a WRITE
BUFFER command in modes five or seven must be performed, followed by a power-cycle.
Download Microcode With Offsets and Save Mode (111b) Description. In this mode, the trans-
fer of vendor-specific microcode from the initiator to the target may be split over two or more
Write Buffer commands. After the complete vendor-specific microcode image has been trans-
ferred from the initiator into the data buffer, the checksum is then verified and the microcode is
saved into a non-volatile memory (i.e. flash memory). The downloaded code shall then be effec-
tive after each power-cycle and reset until another download microcode and save operation is per-
formed. When the Write Buffer command has completed successfully, the target generates a unit
attention condition for all initiators except the one that issued the WRITE BUFFER command.
When reporting the unit attention condition, the target shall set the additional sense code to
MICROCODE HAS BEEN CHANGED.
NOTE: The saved microcode does not become the active code load until a power on reset is per-
formed.
In the Download Microcode With Offsets and Save mode, Buffer ID 0 is the only Buffer ID sup-
ported. If any other Buffer ID value is selected, the target returns CHECK CONDITION status
and sets the sense key to ILLEGAL REQUEST with an additional sense code of INVALID FIELD
IN CDB.
The microcode is written into the data buffer starting at the location specified by the Buffer Offset.
The first Write Buffer command initiating a download microcode with offsets mode operation
must contain a Buffer Offset of zero. If this Buffer Offset is not zero, the target returns CHECK
CONDITION status and sets the sense key to ILLEGAL REQUEST with an additional sense code
of INVALID FIELD IN CDB. Subsequent Write Buffer commands must contain a Buffer Offset
such that the microcode is being downloaded contiguously (i.e. microcode bytes are being down-
loaded in sequential order with no gaps). If this Buffer Offset is incorrect, the target returns
CHECK CONDITION status and sets the sense key to ILLEGAL REQUEST with an additional
sense code of INVALID FIELD IN CDB.
NOTES:
1. Following a successful microcode download and save operation, the target does not do an auto-
matic reset and will continue running off of the old microcode. In order to run off of the new
microcode which has been downloaded and saved, a power-cycle is required.
2. The microcode image that is downloaded via the WRITE BUFFER command includes the con-
troller and servo microcode. In the Download Microcode With Offsets and Save mode, both
the controller microcode and servo microcode are saved into flash following a successful
download.
4-3.32.2 WRITE BUFFER CHECK CONDITION Status
If the Transfer Length field specifies a transfer that exceeds the buffer capacity, the target returns
CHECK CONDITION status and sets the sense key to ILLEGAL REQUEST with an additional
sense code of INVALID FIELD IN CDB.
Data is transferred beginning at the offset within the buffer as specified by the Buffer Offset. If the
initiator fails to conform to the offset boundary requirements returned in the Read Buffer descrip-