Creating a Configuration File

You need to create a configuration file in order to:

• override default compression settings
• use the Google compression option

Configuration File Location

By default, CompLearn will read a configuration file called config.yml placed in a .complearn directory in the path specified by your HOME environment variable. On Linux and Linux-like systems, you may retrieve the HOME environment variable by typing "echo $HOME" command. In Windows systems, to view, change or add a HOME environment variable:

1. Right-click My Computer, and then click Properties.
2. Click the Advanced tab.
3. Click Environment variables.
4. Click one the following options, for either a user or a system variable:
   • Click New to add a new variable name and value.
   • Click an existing variable, and then click Edit to change its name or value.
   • Click an existing variable, and then click Delete to remove it.

For each setting in complearn.conf, a key and value is specified. The general format is specified in this GKeyFile document.

Example:

 # one key value pair per line at most
[complearn]

# directory where modules can be found
    module-path=/usr/lib/complearn/modules
# print extra detailed information
    verbose=yes
# scheduling priority, higher is less CPU
    nice-level=19
[ncd]
    show-labels=yes

ncd Configuration Settings

Settings for the ncd command:

• compressor - The builtin compressor to be used. Valid values are: bzlib, zlib, and blocksort.

Example:

compressor: zlib

Bzip-Specific Configuration Settings

The builtin bzip compressor has 3 settings that may be added to a configuration file:

• blocksize - is an integer from 1 to 9. 9 gives the best compression but takes the most memory. CompLearn's default value is 9.
• workfactor - is an integer from 0 to 250 and controls how the compression phase behaves when presented with the worst case, highly repetitive, input date. CompLearn's default value of 30 gives reasonable behavior over a wide range of circumstances.
• bzverbosity - is an integer from 0 and 4. 0 is silent and greater numbers give increasingly verbose monitoring/debugging output. CompLearn's default value is 0.

Example:

# sample settings for bzip compressor
blocksize:   7
workfactor:  85
bzverbosity: 4

Zlib-Specific Configuration Settings

The builtin zlib compressor has 1 setting that may be added to a configuration file:

• zliblevel - is an integer from 1 to 9. 1 is the fastest and produces the least compression. 9 is the slowest and produces the most compression. CompLearn's default value is 9.

Example:

# sample settings for zlib compressor
zliblevel: 5