ArGest Backup User Guide

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The brutab File

BRU works most effectively when it is properly matched with the backup device it will be using. The proper device settings allow BRU to run at maximum speed and increase its ability to detect and recover from errors.

The device parameters are described in a file that is read by BRU when it begins execution. Normally, the BRU device file is named brutab and is located in the /etc directory. The /etc/brutab file may contain entries for several different devices. This file describes: The name and characteristics of the available archive devices (a description can cover more than one such device). When you provide entries in brutab describing, for example, the size of the archive tape, then the size parameter need not be provided to BRU on the command line when the program is called.

Values (either symbolic or numeric) that your own system generates for errors of various kinds. This allows BRU to respond properly when certain conditions (like end-of-tape or write protect) are encountered. It also lets BRU generate the correct message when an error is detected.

You may have several versions of brutab if you wish. Normally BRU looks for a device parameter file named /etc/brutab. However, you can override this default by setting the BRUTAB environment variable to point to the version of brutab you want to use.

Here’s an example of how to set the BRUTAB environment variable (under the Bourne shell):

$ BRUTAB=/tmp/brutab.new
$ export BRUTAB

The brutab file usually has sample device configurations for many systems on which BRU has already been installed. If your specific device or system is not listed, you can probably find one that is similar. Simply copy the applicable entry and edit it for your device. NOTE: The brutab file must contain at least two entries: One describes the capabilities of the default archive device, and a second describes the capabilities of the standard input device and its error messages. See Appendix A for example brutab file.

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