Quantum DLT-S4, Reference Manual

Page: 178 / 386

Chapter 4 SCSI Commands
MODE SELECT (6) / (10) Command (15h / 55h)
DLT-S4 Interface Reference Guide 144
Data Security Mode Page
(27h)
4
The DLT-S4 drive checks for password protection on the DLT-S4 tape
during the load process and if it is enabled, verifies that the drive has the
same password. If the passwords match, the user can read and write data
on the tape. If they do not match,
READ
and
WRITE
commands will be
rejected and sense data will be presented to the initiator.
Data Security is enabled using a
MODE SELECT
command for the Vendor-
Unique Data Security Mode page. The Data Security settings can be read
using a
MODE SENSE
command for the Data Security Mode page. The
password will not be returned in the
MODE SENSE
data. The password is
written to the tape in response to a
WRITE
command when positioned at
the beginning of the tape (
WRITE
from BOT). Action code 0x08 (
Set Drive
Password
and
Write to Tape Immediately
) does not require a
WRITE
command to cause the password to be written to tape, it is written
automatically prior to the completion of the
MODE SELECT
command.
Figure 77 shows the page that controls uses a password verification
mechanism to prevent or allow reading and writing the data to the tape.
Its primary function is to provide a means of preventing unauthorized
access to data on a DLT-S4 native cartridge. It has no impact on Back Read
cartridges.
Figure 77 Data Security Mode
Page — Data Format
Bit
7 6 5 4 3 2 1 0
Byte
0 PS (0) 0 Page Code (27h)
1 Additional Page Length (32h)
2 Reserved PAX PCP PWF Reserved CRA CWA
3
Reserved
4
Reserved Password Selection Scope
5 Reserved Action Code
6 Reserved
7 Reserved Number of Passwords Supported
8 — 9
Reserved APB APD PA TPP DPS PM