| Software | ||
|---|---|---|
 | Chapter 3. YaST — Configuration |  |
| The YaST Control Center | Hardware | |
| Software | ||
|---|---|---|
| | Chapter 3. YaST — Configuration | |
| The YaST Control Center | Hardware | |
The installation source is the medium containing the software to install. YaST can administer a number of different installation sources. It enables their selection for installation or update purposes.
When this module is started, a list displaying all previously registered sources is displayed. Following a normal installation from CD, only the installation CD is listed. Click to include additional sources in this list. You can add removable media, such as CDs and DVDs, and network connections, such as NFS and FTP. Even directories on the local hard disk can be selected as the installation medium. See the detailed YaST help text.
During the installation or update, YaST can take multiple installation sources into consideration. Therefore, all registered sources have an activation status in the first column of the list. Click to activate or deactivate individual installation sources. During the installation of software packages or updates, YaST selects the suitable installation source from the range of activated installation sources.
If you exit the module with , the current settings are saved and applied to the configuration modules and .
The YaST Online Update (YOU) enables the installation of important updates and improvements. The respective patches are available for download on the SuSE FTP server and various mirror servers. Under , select one of the various servers. When you select server, the respective URL is copied to the input field below, where it can be edited. You can also specify local URLs in the form “file:/my/path” or simply “/my/path”. Expand the existing list with additional servers using . Click to modify the settings of the currently selected server.
When the module starts, is active, enabling determination of whether individual patches should be loaded. To apply all available update packages, deactivate this option. However, depending on the bandwidth of the connection and the amount of data to transmit, this can result in long download times.
If you activate , all available patches, installable packages, and descriptions are downloaded from the server. If this box is not activated (default), only retrieve patches not yet installed on your system.
Additionally, there is a possibility to update your system automatically. Click to configure a process that automatically looks for updates and apply them on a daily basis. This procedure is fully automated and does not require any interaction. Of course, this only works if a connection, such as an Internet connection, to the update server exists at the time of the update.
If you decide to perform a manual update (default), click to load a list of all available patches and start the package manager, described in Section “Installing and Removing Software”. In the package manager, the filter for YOU patches is activated, enabling selection of updates to install. Patches whose installation is advisable are preselected. Normally, you should accept this suggestion.
After making your selection, click in the package manager. All selected updates are then downloaded from the server and installed on your machine. Depending on the connection speed and hardware performance, this may take some time. Any errors are displayed in a window. If necessary, skip the respective package. Prior to the installation, some patches may open a window displaying details, allowing you to confirm the installation or skip the package.
While the updates are downloaded and installed, track actions in the log window. Following the successful installation of all patches, exit YOU with . If you do not need the update files after the installation, delete them with . Finally, SuSEconfig is executed to adapt the system configuration to the new circumstances.
The Patch CD Update is for SuSE Linux Enterprise Server customers. Patches are installed from CD instead of downloaded from a FTP server.
This module enables installation, uninstallation, and updating of software on your machine. The following paragraphs provide some background information about the management of software.
In Linux, software is available in the form of packages. Normally, a package contains everything needed for a program (such as an editor, a compiler, and so on). Usually, this includes the actual program, associated configuration files, and documentation. Often, a package containing the source files for the respective program is also available. The sources are not needed for running the program. Nevertheless, you may want to install the sources to compile a custom version of the program. In Linux, this is possible and permitted.
Some packages depend on other packages. This means that the software of the respective package only works properly if another package is also installed (package dependency). Furthermore, the installation (not only the operation) of some packages is only possible if certain other packages are installed, perhaps because the installation routine needs specific tools. Accordingly, such packages must be installed in the correct sequence. Moreover, there are some packages with identical or similar functionalities that serve the same purpose. If these package make use of the same system resource, they should not be installed concurrently (package conflict). 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 complicated.
All these factors must be taken into consideration when installing, uninstalling, and updating software. Fortunately, YaST provides an extremely efficient tool for this purpose: the software installation module, usually referred to as the package manager. 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 select 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 restricted by means of suitable filters. Thus, the package manager facilitates the management of software packages and is a valuable tool for maintaining your system.
To change the software selection on your system with the package manager, select in the YaST Control Center. The dialog window of the package manager is displayed as shown in Figure 3.4: “YaST: Package Manager”.
The window comprises various frames. The frame sizes can be modified by clicking and moving the lines separating the areas. The contents of the frames and their use are described below.
Selecting all packages of an installation one by one would be vary laborious and time-consuming. Therefore, the package manager offers various filter methods for arranging the packages in categories and limiting the number of displayed packages. The filter window is located to the left under the menu bar. It controls and displays various filter methods. The filter selection box at the top determines what will be displayed in the lower part of the filter window. Click the filter selection box to select a filter from the list of available filters.
At start-up, the filter is active. This filter groups the program packages according to their application purpose, such as “Multimedia” or “Office Applications.” The various groups of the filter are listed under the filter selection box. The packages already installed on the system are preselected. Click the status box at the beginning of a line to toggle the status flags of a selection. You can also select a status directly by right-clicking the selection and using the context menu. The individual package window to the right displays the list of packages included in the current selection, enabling selection and deselection of individual packages.
The filter provides a more technical overview of the range of packages and is suitable for users who are familiar with the package landscape of SuSE Linux. This filter sorts the program packages by subjects, such as “Applications,” “Development,” and “Hardware,” in a tree structure to the left. The more you expand the branches, the more specific the selection is and the fewer packages are displayed in the individual package window to the right.
Moreover, the filter provides the possibility to display all packages in alphabetic order. To do this, select in the top level. As SuSE Linux contains a large number of packages, it may take some time until this long list is displayed.
The function is the easiest way to find a specific package. By specifying various search criteria, restrict the filter so much that often only one package is displayed in the individual package window. Enter a search string and use the check boxes to determine where to search for this string (in the name, in the description, or in the package dependencies). Advanced users can even define special search patterns using wild cards and regular expressions and search the package dependencies in the “Provides” and “Requires” fields. For example, software developers who download source packages from the Internet can use this function to determine which package contains a specific library needed for compiling and linking this package.
In addition to the filter, all lists of the package manager feature a quick search for the current list content. For example, simply enter the initial letter of a package name to move the cursor to the first package in the list whose name begins with this letter. The cursor must be in the list (by clicking the list).
After selecting the packages for installation, update, or deletion, use the filter selection box to view the installation summary. It shows what will happen with packages when you click . Use the check boxes to the left to filter the packages to view in the individual package window. If, for example, you merely want to check which packages are already installed, start the package manager and deactivate all check boxes except .
Of course, the package status in the individual package window can be changed as usual. However, the respective package may no longer meet the search criteria. To remove such packages from the list, update the list with .
As mentioned above, a list of individual packages is displayed to the right in the individual package window. The content of this list is determined by the currently selected filter. If, for example, the filter is selected, the individual package window displays all packages of the current selection.
In the package manager, each package has a status that determines what to do with the package, such as “Install” or “Delete”. This status is shown by means of a symbol in a status box at the beginning of the line. Toggle the status with a mouse click or select it directly by opening the context menu by right-clicking. Depending on the current situation, some of the possible status flags may not be available for selection. For example, a package that has not yet been installed cannot be set to “Delete.” View the available status flags with -> .
The package manager offers the following package status flags:
This package is not installed and will not be installed.
This package is not yet installed but will be installed.
This package is already installed and will not be changed.
This package is already installed and will be replaced by the version on the installation medium.
This package is already installed and will be deleted.
This package is not installed and will never be installed. It will be treated as if it does not exist on any of the installation media. If a package would automatically be selected to resolve dependencies, this can be prevented by setting the package to “Taboo.” However, this may result in inconsistencies that must be resolved manually (dependency check). Thus, “Taboo” is mainly intended for expert users.
This package is installed and should not be modified, as unresolved dependencies from other packages exist or could arise. Third-party packages (packages without SuSE signature) are automatically assigned this status to prevent them from being overwritten by later versions existing on the installation media. This may cause package conflicts that must be resolved manually (for experts).
This package has been automatically selected for installation, as it is required by another package (resolution of package dependencies).
To deselect such a package, you may need to use the status “Taboo” (see above).
This package is already installed. However, as another package requires a newer version of this package, the installed version will automatically be updated.
This package is already installed, but existing package conflicts require this package be deleted. For example, this may be the case if the current package has been replaced by a different package. However, this does not happen very often.
This packages has been automatically selected for installation because it is part of a predefined selection, such as “Multimedia” or “Development.”
This package is already installed, but a newer version exists on the installation media. This package is part of a predefined selection, such as “Multimedia” or “Development,” selected for update and will automatically be updated.
This package is already installed, but a predefined selection (such as “Multimedia” or “Development”) requires this package be deleted. This does not happen very often.
Additionally, decide to install or not to install the sources for a package. This information complements the current package status and cannot be toggled with the mouse or selected directly from the context menu. Instead, a check box at the end of the package line enables selection of the source packages. This option can also be accessed under .
Also install the source code.
The sources will not be installed.
The font color used for various packages in the individual package window provides additional information. Installed packages for which a newer version is available on the installation media are displayed in blue. Installed packages whose versions numbers are higher than those on the installation media are displayed in red. However, as the version numbering of packages is not always linear, the information may not be perfect, but should be sufficient to indicate problematic packages. If necessary, check the version numbers in the information window.
The tabs in the bottom right frame provide various information about the selected package. The description of the selected package is automatically active. Click the other tabs to view technical data (package size, group, and so forth), the list of dependencies from other packages, or the version information.
The resource window at the bottom left displays the disk space needed for your current selection of software on all currently mounted file systems. The colored bar graph grows with every selection. As long as it remains green there is sufficient space. The color of the bar color slowly changes to red as you approach the limit of disk space. If you select too many packages for installation, an alert is displayed.
The menu bar at the top left of the window provides access to most of the functions described above and a number of other functions that cannot be accessed in any other way. It contains the following four menus:
Select -> to save a list of all installed packages in a text file. This is recommended if you want to replicate a specific installation scope at a later date or on another system. A file generated in this way can be imported with and generates the same package selection as was saved. In both cases, define the location of the file or accept the suggestion.
To exit the package manager without saving changes to the package selection, click . To save your changes, select . In this case, all changes are applied and the program is terminated.
The items in the menu always refer to the package currently displayed in the individual package window. Although all status flags are displayed, you can only select those possible for the current package. Use the check boxes to determine whether to install the sources of the package. The item opens a submenu listing all package status flags. However, these do not merely affect the current package, but all packages in this list.
The menu offers options for handling package dependencies and conflicts. If you have already manually selected packages for installation, click to view the list of packages that the package manager automatically selected to resolve dependencies. If there are still unresolved package conflicts, an alert is displayed and solutions suggested.
If you set package conflicts to “Ignore”, this information will be saved permanently in the system. Otherwise, you would have to set the same packages to “Ignore” each time you start the package manager. To unignore dependencies, click .
-> provides a brief explanation of the package manager functionality. A detailed description of the various package flags is available under . If you prefer to operate programs without using the mouse, click to view a list of shortcuts.
and are located in the information window. If you click , the package manger checks if the current package selection results in any unresolved package dependencies or conflicts. In the event of unresolved dependencies, the required additional packages are selected automatically. For package conflicts, the package manager opens a dialog that shows the conflict and offers various options for solving the problem.
If you activate , any change of a package status triggers an automatic check. This is a useful feature, as the consistency of the package selection is monitored permanently. However, this process consumes resources and can slow down the package manager. For this reason, the autocheck is not activated by default. In either case, a consistency check is performed when you confirm your selection with .
In the following example, sendmail and postfix may not be installed concurrently. Figure 3.5: “Conflict Management of the Package Manager” shows the conflict message prompting you to make a decision. postfix is already installed. Accordingly, you can refrain from installing sendmail, remove postfix, or take the risk and ignore the conflict.
Ignoring a conflict is strongly discouraged, as the stability and operability of your system can no longer be guaranteed under these conditions.
This module enables an update of the version installed on your system. During operation, you can only update application software, not the SuSE Linux base system. To update the base system, boot the computer from an installation medium, such as the CD. When selecting the installation mode in YaST, select instead of .
The procedure for updating the system is similar to the new installation. Initially, YaST examines the system, determine a suitable update strategy, and present the results in a suggestion dialog like that in Figure 3.6: “Suggestion Dialog for Updates”. Click the individual items with the mouse to change any details. Some items, such as and , are covered in the section explaining the installation procedure. Therefore, the following paragraphs only cover update-specific settings.
In case several versions of SuSE Linux are installed on your system, this item enables you to select a partition for the update from the list.
Here, set the update method for your system. Two options are available. See Figure 3.7: “Update Options”.
To update the entire system to the latest software versions, you can select one of the predefined selections. These selections are the same as those offered during the installation. They make sure new packages that did not exist previously are also installed.
This option merely updates packages that already exist on the system. No new features will be installed.
Additionally, you can use to remove packages that do not exist in the new version. By default, this option is preselected to prevent outdated packages from unnecessarily occupying hard disk space.
Click to start the package manager and select or deselect individual packages for update. Any package conflicts should be resolved with the consistency check. The use of the package manager is covered in detail in Section “Installing and Removing Software”.
During the update, the configuration files of some packages may be replaced by those of the new version. As you may have modified some of the files in your current system, the package manager normally makes backup copies of the replaced files. With this dialog, determine the scope of these backups.
This backup does not include the software. It only contains the respective configuration files.
The system update is a very complex procedure. For each program package, YaST must check which version is installed on the computer and what needs to be done to replace the old version with the new version correctly. YaST also tries to adopt any personal settings of the installed packages. However, some configurations may cause problems after the update if the old configuration is unable to handle the new program version as expected or if unexpected inconsistencies arise between various configurations.
The older the existing version is and the more the configuration of the packages to update diverges from the standard, the more problematic the update will be. Sometimes, the old configuration cannot be adopted correctly. In this case, an entirely new configuration must be made. Before starting the update, the existing configuration should be saved.
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| The YaST Control Center |  | Hardware |
