42 Introduction to Configuration Switches
Data Compression—Switches 1 and 2
Switches 1 and 2 are used to configure the way in which data compression is
set for the drive. The following table shows the available options; whether
data compression is enabled or disabled at power-on, and whether the host
can subsequently control compression:
Switch 1 controls the default state of the drive at power-on:
n
If it is ON, the default is compression enabled, which means that data will
be compressed without the knowledge of the host.
n
If it is OFF, the default is compression disabled.
Switch 2 controls whether or not the host can change the drive’s data
compression status:
n
If it is ON, data compression can be set on or off using appropriate SCSI
commands sent from the SCSI tape driver or your backup software.
n
If it is OFF, the host cannot change the default compression setting.
Note
By default, the drives and autoloaders will decompress data
when reading a compressed tape, regardless of the settings of
switches 1 and 2. Decompression can be turned off through the
DC Characteristics Page of the SCSI
MODE SELECT
command.
Media Recognition System (MRS)—Switch 3 or 8
Note
The Media Recognition System is described in the
Hardware
Intergration Guide
, Volume 1 of the HP DDS Technical Manual
(see the Introduction).
Silicon Graphics SGI
On
On
Off
On
On
Off
Off
On
Sun Solaris
On
On
Off
Off
On
On
Off
Off
1
2
3
4
5
6
7
8
Switch 1 Switch 2
Data Compression at Power-On
Control of Compression
On
On
Enabled
Host control
On
Off
Enabled
No host control
Off
On
Disabled
Host control
Off
Off
Disabled
No host control
Summary of Contents for C1537A
Page 22: ...22 IBM AIX Servers and Workstations ...
Page 26: ...26 Linux Servers and Workstations ...
Page 32: ...32 Silicon Graphics SGI ...
Page 44: ...44 Introduction to Configuration Switches ...
Page 62: ...62 index ...
