Following guiding rules were followed while compiling this document:

I tried to elucidate hierarchical aspects and lower levels of the system.

You are required to seek help from (in approximate order of importance, starting with the most important sources):

	Note
	For detailed documentation, you may need to install the corresponding documentation package named with "-doc" as its suffix.

This document refers to some command names followed by the number in parenthesis , such as bash(1). This means that you are encouraged to obtain information from the manpage by typing the following on the shell command prompt:

$ man 1 bash 

This document provides information through the following simplified presentation style with bash(1) shell command examples and bullets:

# <command in root account>
$ <command in user account>

These shell prompts distinguish account used and correspond to PS1='\$' and PS2=' ' environment variables. These values are chosen for the sake of readability of this document and are not typical on actual installed system.

	Note
	See the meaning of the PS1 and PS2 environment variables in the manpage of bash(1) command.

The popcon data was presented as the objective measure for the popularity of each package. It was downloaded on 2009-01-18 and contains the total submission of 79097 reports over 91823 binary packages and 20 architectures.

	Note
	Please note that the amd64 unstable archive contains only 24396 packages currently. The popcon data contains reports from many old system installations.

The popcon number preceded with "V:" for "votes" is calculated by 100 * (the popcon submissions for the package executed recently on the PC)/(the total popcon submissions).

The popcon number preceded with "I:" for "installs" is calculated by 100 * (the popcon submissions for the package installed on the PC)/(the total popcon submissions).

	Note
	The popcon figures should not be considered as absolute measures of the importance of packages. There are many factors which can skew statistics. For example, some system participating popcon may have mounted directories such as /bin with "noatime" option for system performance improvement and effectively disabled "vote" from such system.

The package size data was also presented as the objective measure for each package. It is based on the "Installed-Size:" reported by "apt-cache show " command (currently on amd64 architecture for the unstable release). The reported size is in KB (unit for 1024 bytes).

	Note
	A package with a small numerical package size may indicate that the package in the unstable release has a dummy package which installs other packages with significant contents by the dependency. The dummy package enables a smooth transition or split of the package.

Please file bug reports on "debian-reference" package using reportbug(1) if you find any issues. For simple spell errors and grammar corrections, you may alternatively edit the source text available as Debian Reference wiki page at http://wiki.debian.org/DebianReference and tell me to update the document.