User's Guide

Quantum Scalar Intelligent Libraries SCSI Reference Guide Guide 93
Write Buffer (3Bh)
What the Library Does With This Command
The library will receive a requested buffer of data and write it to the appropriate internal storage.
Command Usage
This command can be used primarily for enhanced domain validation (using the echo buffer mode). The
initiator can either transfer the data with a single WRITE BUFFER command, or it can also transfer it in
blocks utilizing offsets into the buffer.
Write Buffer CDB Format
The WRITE BUFFER CDB format is shown in the following table.
Mode – The supported modes are:
• 2h – Data
• Ah – Echo Buffer
In Data Mode, an amount of data specified by the Parameter List Length is targeted for the buffer defined
by the Buffer ID field, starting at the specified Buffer Offset. Buffer IDs are assigned beginning with zero,
and are assigned contiguously. Buffer ID code assignments for the WRITE BUFFER command are the
same as for the READ BUFFER command.
In Echo Buffer Mode, the amount of data specified by the Parameter List Length is transferred from the
initiator to the echo buffer. The Buffer ID and Buffer Offset fields are ignored in this mode.
Note: The Echo Buffer is supported only if the library control path is provided by a tape drive.
Buffer ID – This field specifies which buffer the request is for. The IDs are the same for both the READ
BUFFER and WRITE BUFFER commands. The IDs supported by the library, along with their primary use,
are listed in Table 60
on page 63.
Table 91 WRITE BUFFER CDB format
Bit
Byte
76543210
0Op Code (3Bh)
1 Logical Unit Number Rsvd Mode
2 Buffer ID
3
:
5
Buffer Offset
6
:
8
Parameter List Length
9 Control