IBM TS2340 User Guide - Page 49

Buffered Mode, Compression, Fail Degraded Media, Logging, Maximum Size of the Log File, except

Page 49 highlights

AIX Device Driver (Atape) The installation default is zero (use variable length) except for the IBM 7332 4mm Tape Cartridge Autoloader, for which the default is a fixed block size of 1024 bytes. Buffered Mode When a write command is processed, the data is either stored directly on the physical tape or buffered in the tape device. Buffering can increase the device performance. The installation default is On (use Buffered mode). Compression Hardware compression is implemented in the device hardware. This parameter turns the compression feature On and Off. If compression is enabled, then the effective performance can increase based on the compressibility of the data. The installation default is On (use compression). Fail Degraded Media This parameter controls whether the device driver fails a tape operation when degraded media is detected by the IBM TotalStorage Enterprise Tape System 3590. If a tape is loaded and the IBM 3590 cannot read the positioning information from the tape, the device driver is notified when the first command is sent to the tape drive. If this parameter is set to On, the device fails the command and returns a media error to the application. If this parameter is set to Off, the device driver does not fail the command. Degraded media is a correctable condition that prevents the IBM TotalStorage Enterprise Tape System 3590 from performing high speed Locate operations. A Locate command can take over 20 minutes, depending on the desired position and the amount of data on the tape. This parameter is intended for use by real time applications that cannot tolerate long Locate commands. The installation default is Off (do not fail the tape operation if degraded media is detected). Logging This parameter turns the volume information logging on and off. If logging is set to On, the statistical information about the device and media is saved in a log file when a tape is unloaded. If logging is set to Off, the information is not saved. This parameter has no effect on error logging because error logging is always enabled. For more information, refer to "Device and Volume Information Logging" on page 43. The installation default is Off (no logging). Maximum Size of the Log File This parameter specifies the number of entries made before the log file starts to wrap. Each entry is approximately 2 KB (2048 bytes). After the log file starts to wrap, the number of entries stays constant. Each time a new entry is made, the oldest entry is overlaid. For more information, refer to "Device and Volume Information Logging" on page 43. The installation default is 500. Chapter 3. AIX Tape and Medium Changer Device Driver 31

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The installation default is zero (use variable length)
except
for the IBM 7332 4mm
Tape Cartridge Autoloader, for which the default is a fixed block size of 1024 bytes.
Buffered Mode
When a write command is processed, the data is either stored directly on the
physical tape or buffered in the tape device. Buffering can increase the device
performance.
The installation default is On (use Buffered mode).
Compression
Hardware compression is implemented in the device hardware. This parameter
turns the compression feature On and Off. If compression is enabled, then the
effective performance can increase based on the compressibility of the data.
The installation default is On (use compression).
Fail Degraded Media
This parameter controls whether the device driver fails a tape operation when
degraded media is detected by the IBM TotalStorage Enterprise Tape System 3590.
If a tape is loaded and the IBM 3590 cannot read the positioning information from
the tape, the device driver is notified when the first command is sent to the tape
drive. If this parameter is set to On, the device fails the command and returns a
media error to the application. If this parameter is set to Off, the device driver
does not fail the command.
Degraded media is a correctable condition that prevents the IBM TotalStorage
Enterprise Tape System 3590 from performing high speed
Locate
operations. A
Locate
command can take over 20 minutes, depending on the desired position and
the amount of data on the tape. This parameter is intended for use by real time
applications that cannot tolerate long
Locate
commands.
The installation default is Off (do not fail the tape operation if degraded media is
detected).
Logging
This parameter turns the volume information logging on and off. If logging is set
to On, the statistical information about the device and media is saved in a log file
when a tape is unloaded. If logging is set to Off, the information is not saved. This
parameter has no effect on error logging because error logging is always enabled.
For more information, refer to “Device and Volume Information Logging” on page
43.
The installation default is Off (no logging).
Maximum Size of the Log File
This parameter specifies the number of entries made before the log file starts to
wrap. Each entry is approximately 2 KB (2048 bytes). After the log file starts to
wrap, the number of entries stays constant. Each time a new entry is made, the
oldest entry is overlaid. For more information, refer to “Device and Volume
Information Logging” on page 43.
The installation default is 500.
AIX Device Driver (Atape)
Chapter 3. AIX Tape and Medium Changer Device Driver
31