During the installation process, you are given the opportunity to select additional software to install. Rather than picking individual software packages from the &num-of-distrib-pkgs; available packages, this stage of the installation process focuses on selecting and installing predefined collections of software to quickly set up your computer to perform various tasks. So, you have the ability to choose tasks first, and then add on more individual packages later. These tasks loosely represent a number of different jobs or things you want to do with your computer, such as Desktop environment, Web server, or Print server You should know that to present this list, the installer is merely invoking the tasksel program. It can be run at any time after installation to install more packages (or remove them), or you can use a more fine-grained tool such as aptitude. If you are looking for a specific single package, after installation is complete, simply run aptitude install package, where package is the name of the package you are looking for. . lists the space requirements for the available tasks. Some tasks may be pre-selected based on the characteristics of the computer you are installing. If you disagree with these selections you can deselect them. You can even opt to install no tasks at all at this point. In the standard user interface of the installer, you can use the space bar to toggle selection of a task. Unless you are using the special KDE or Xfce/LXDE CDs, the Desktop environment task will install the GNOME desktop environment. It is not possible to interactively select a different desktop during the installation. However, it is possible to get &d-i; to install a KDE desktop environment instead of GNOME by using preseeding (see ) or by adding the parameter desktop=kde at the boot prompt when starting the installer. Alternatively the more lightweight Xfce and LXDE desktop environments can be selected by using desktop=xfce or desktop=lxde. Some CD images (businesscard, netinst and DVD) also allow selection of the desired desktop environment from the graphical boot menu. Select the Advanced options option in the main menu and look for Alternative desktop environments. Note that this will only work if the packages needed for the desired desktop environment are actually available. If you are installing using a single full CD image, they will need to be downloaded from a mirror as most needed packages are only included on later CDs; installing KDE, Xfce or LXDE this way should work fine if you are using a DVD image or any other installation method. The various server tasks will install software roughly as follows. DNS server: bind9; File server: samba, nfs; Mail server: exim4, spamassassin, uw-imap; Print server: cups; SQL database: postgresql; Web server: apache2. The Standard system task will install any package that has a priority standard. This includes a lot of common utilities that are normally available on any Linux or Unix system. You should leave this task selected unless you know what you are doing and want a really minimal system. Once you've selected your tasks, select &BTN-CONT;. At this point, aptitude will install the packages that are part of the selected tasks. If a particular program needs more information from the user, it will prompt you during this process. You should be aware that especially the Desktop task is very large. Especially when installing from a normal CD-ROM in combination with a mirror for packages not on the CD-ROM, the installer may want to retrieve a lot of packages over the network. If you have a relatively slow Internet connection, this can take a long time. There is no option to cancel the installation of packages once it has started. Even when packages are included on the CD-ROM, the installer may still retrieve them from the mirror if the version available on the mirror is more recent than the one included on the CD-ROM. If you are installing the stable distribution, this can happen after a point release (an update of the original stable release); if you are installing the testing distribution this will happen if you are using an older image.