Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 56 — #82

2.3.4 Installing and Removing Software

This module enables installation, uninstallation, and update of software

on your machine. In Linux, software is available in the form of packages.

Normally, a package contains everything needed for a program (such as an

editor or a compiler). Usually, this includes the actual program, associated

conﬁguration ﬁles, and documentation. A package containing the source

ﬁles for the respective program is normally available as well. The sources

are not needed for running the program. However, you may want to install

the sources to compile a custom version of the program.

Some packages depend on other packages. This means that the software of

the package only works properly if another package is also installed (pack-

age dependency). Furthermore, the installation (not only the operation) of

some packages is only possible if certain other packages are installed, per-

haps because the installation routine needs speciﬁc tools. Accordingly, such

packages must be installed in the correct sequence. There are some pack-

ages with identical or similar functionalities. If these packages use the same

system resource, they should not be installed concurrently (package con-

ﬂict). Dependencies and conﬂicts can occur between two or more packages

and are sometimes very complex. The fact that a speciﬁc package version

may be required for smooth interaction can make things even more compli-

cated.

All these factors must be taken into consideration when installing, unin-

stalling, and updating software. YaST features a dedicated software instal-

lation tool called the package manager, which assists with this. When the

package manager is started, it examines the system and displays installed

packages. If you select additional packages for installation, the package

manager automatically checks the dependencies and selects any other

needed packages (resolution of dependencies). If you unknowingly se-

lect conﬂicting packages, the package manager indicates this and submits

suggestions for solving the problem (resolution of conﬂicts). If a package

needed by other installed packages is accidentally marked for deletion, the

package manager issues an alert with detailed information and alternative

solutions.

Apart from these purely technical aspects, the package manager provides

a well-structured overview of the range of packages in SUSE LINUX. The

packages are arranged by subjects and the display of these groups is re-

stricted by means of suitable ﬁlters.

2.3. Software