User's Guide

Chapter 3 Emulated DLT7000 SCSI Commands
Read Buffer (3Ch)
236 Quantum DX-Series Software Interface Guide
Once the size of the buffer is known, Mode 2 (Data Only, see Section
5.14.2) can be used to transfer the data across the SCSI Bus.
Combined Header
and Data Mode
3
In this mode, the tape drive returns a 4-byte header followed by data
bytes. The drive terminates the DATA IN phase when the Allocation
Length bytes of header and data have been transferred or when all
available data has been transferred to the initiator, whichever is less. The
4-byte READ BUFFER header is followed by data bytes from the target
data buffer. The figure below illustrates the format of the header.
Table 185 READ
BUFFER Header -
Data Format.
Bit/Byte 7 6 5 4 3 2 1 0
0
1-3
2
3-5
6-8
9
Reserved
(MSB)
Available Length
(LSB)
Buffer ID
(MSB)
Buffer Offset
(LSB)
(MSB)
Allocation Length
(LSB)
Unused Reserved
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