User's Guide

Page 128 DDS-4 SCSI Interface Manual, Rev. B
REPORT DENSITY SUPPORT (44h)
The REPORT DENSITY SUPPORT command requests transfer of information
regarding the supported densities for the logical unit to the host.
REPORT DENSITY SUPPORT Command Descriptor Block
The following table shows the layout of the CDB for REPORT DENSITY SUPPORT.
Byte
Bits
7 6 5 4 3 2 1 0
0 0 1 0 0 0 1 0 0
1 0 0 0 0 0 0 0 Media
2 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
4 0 0 0 0 0 0 0 0
5 0 0 0 0 0 0 0 0
6 0 0 0 0 0 0 0 0
7 Allocation Length
8 Allocation Length—LSB
9 vendor unique* 0 0 0 0 Flag Link
* This vendor-unique field is reserved and must be set to zero.
Command Descriptor Block Field Description
The following table defines the fields in the CDB for REPORT DENSITY SUPPORT.
Field
Name Bytes Bits Description
Media 1 0 A Media bit of zero indicates that the drive will return density support
data blocks of the densities supported by the logical unit for any
supported media. A Media bit of one indicates the drive will return
density support blocks for the densities supported by the mounted
media.
Allocation
Length
7-8 The Allocation Length specifies the maximum number of bytes that the
drive may return. Truncation will occur if the Allocation Length is less
than the number of bytes in the requested density support data blocks.
REPORT DENSITY Response Data
The response data for the REPORT DENSITY SUPPORT command contains
• A four byte Report Density Support Header
• One or more Report Density Support Data Block Descriptors
The density support data blocks follow the header. The density support data blocks
are in numerical ascending order of the primary density code value.