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Ubuntu Linux--Would You Like Some Community With That? - page 2

Looking at Ubuntu

  • February 3, 2005
  • By Bill von Hagen

This section focuses on the default 4.10 (Warty) installation process. Installation is largely a misnomer for the Hoary live CDs, which boot and run from CD on an existing system without disturbing anything that's already there (though they will take advantage of existing swap partitions). Live CD "installs" still prompt for some information, such as the language and keyboard layout that you want to use, and do so in the same interactive framework as when installing Ubuntu to disk.

By default, Ubuntu installs a desktop system centered around the GNOME desktop. Server-type or custom-hardware installs are still possible through the extensive options that you can read about by pressing F1 at the initial Ubuntu install screen. For example, to install a minimal system, you specify "custom" at the initial prompt and must then bypass automatic updates later on in the install. This will give you a basic, command-line system that you can tweak to your heart's content using apt-get before breaking out your collection of VT100s or H19s.

After pressing Return to begin my initial Ubuntu 4.10 install, I immediately thought I was having a flashback to Yggdrasil days (http://en.wikipedia.org/wiki/Yggdrasil_Linux) or was accidentally installing Slackware. See Figure 1 for a shot of one of the 4.10 installation dialogs. Luckily, at that point, the epiphany occurred and I realized that my mind had been warped by graphical bells and whistles. What I was actually seeing "what I needed to see." An interesting concept--a modern Linux distribution that serves people who might not have 256MB video cards and a Terabyte of disk space. Even my toaster has SVGA nowadays, but it's still nice to see an installer that will easily work on 32-bit PC hardware of almost any vintage.

Warty's installation process is a two-phase process. The first captures basic information about the language and keyboard layout that you want to use, and then probes and configures your system's hardware. It provides its own disk partitioner, which supports ext2, ext3, ReiserFS, JFS, XFS, and FAT16 and FAT32 filesystems, as well as software RAID and logical volumes. By default, the partitioner creates a single swap partition and a single ext3 filesystem. The partitioner can be a tad confusing if you opt for manual partitioning, but works nicely once you get the hang of it.

After partitioning the disk, the installer installs the base system, copies remaining packages to the disk, installs GRUB, and then ejects the CD and reboots into the second phase of the installer. The second phase installer enables you to create the system's default user and then installs the packages that were formerly cached to disk and, optionally, updates to those packages over the net. Figure 2 shows a sample screen of the vast number of package installs during the second phase of the installer. GUI-lovers, avert your eyes!

Unique to Ubuntu and "Live" distributions such as Knoppix is the fact that you do not create a superuser account or set a superuser password. In Ubuntu, the user whose account you create during the second phase of the install process has the ability to run "execute as root" process (using sudo under the covers) and can even start a root shell in a terminal window from one of the desktop menus. Figure 3 shows the type of dialog that displays whenever you attempt to execute an application that uses root privileges. Because Ubuntu is using sudo under the covers, the password that you must type is the password of the user that is currently logged in--typically yourself. Frankly, this is somewhat confusing for many people since you are already logged in as that user, but this is the wrong place for a discussion of the history and implementation of Linux/Unix security mechanisms and ways of maintaining backward compatibility.

If you're using Ubuntu in a commercial setting, the implications of giving normal users the ability to run privileged commands requires some sysadmin forethought. It requires a significant amount of trust in anyone with physical access to anyone else's system, but it is a great way to discourage people from asking for or using the root account when it isn't actually necessary. Whether or not sudo is a complete replacement for root access on an installed systems is a philosophical discussion that is scheduled to complete shortly after the vi/emacs flames wars finish.

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