User's Manual

DLT4000 SCSI Interface
DLT4000/DLT4500/DLT4700 Cartridge Tape Subsystem 8-127
The data to be transferred is preceded by a 4-byte header consisting entirely of
reserved bytes. This header is discarded (not stored into the buffer). The buffer offset
field must be zero for this mode.
8.4.26.2 Write Data
Similar to mode 000b, except there is no header in the data passed to the target. The
Buffer Offset must be zero. Potential buffer overruns are detected and the command is
rejected.
8.4.26.3 Download Microcode
Using buffer offsets, the host can download the firmware image into the target's buffer
in pieces. These commands do not cause the new image to become active. A
Download and Save mode Write Buffer command must be issued.
The tape drive must be empty to allow downloading of an image. This is to safeguard
against accidentally starting a firmware update. If a cartridge is loaded when all or
part of a firmware image has been downloaded, another WRITE BUFFER with
Download mode will be rejected. Overlapping or nonconsecutive downloading of the
image data is not supported. The firmware image must be downloaded in integral
multiples of 4K bytes.
Any error on a Write Buffer command causes any downloaded image data to be
discarded, and the download must be restarted from the beginning.
8.4.26.4 Download Microcode and Save
This mode can be used to download and save the entire image at once, or to download
the image data and save it, or to cause a save operation after all the image data has
been downloaded using the Download only mode. This mode of the command causes
the image data to be verified and the Flash EEPROM firmware area to be updated.
During the reprogramming, the Write Protect and Drive Activity LEDS on the drive's
front panel will blink.