Reference Guide

Chapter 4 SCSI Commands
WRITE BUFFER Command (3Bh)
DLT-S4 Interface Reference Guide 342
Table 194 WRITE BUFFER
Command Descriptor Block
—
Field Descriptions
Write Combined Header
and Data Mode (00h)
4
The data to be transferred is preceded by a 4-byte header consisting
entirely of reserved bytes. The drive discards this header (it is not stored
in the buffer).
The Buffer Offset field must be set to 0 for this mode.
Write Data Mode (02h) 4 This mode is similar to Header and Data Mode, except that there is no
header in the data passed to the drive. The drive detects any potential
buffer overruns and rejects the
WRITE BUFFER command.
Download Microcode
Mode (04h)
4
This mode uses this mode to download the firmware image into the
drive’s buffer. A
WRITE BUFFER command with a mode of DOWNLOAD
MICROCODE
does cause the new image to become active. A Download
Microcode and Save Mode
WRITE BUFFER command must be issued for
the image to become active.
Field Description
Mode The drive supports the following values in this field.
Mode Description
00h Write Combined Header and Data
02h Write Data
04h Download Microcode
05h Download Microcode and Save
0Ah Write Data to Echo Buffer
Buffer ID The modes described for the Mode field only support a Buffer ID of 0, except Echo
Buffer mode, which ignores the Buffer ID field. If the Buffer ID field is a value other
than 0, the drive rejects the command. The drive also detects and rejects commands
that would overrun the buffer.
Buffer Offset This field contains the offset in bytes from the beginning of the buffer.