Category: Linux

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Fedora Core 5

I’ve been using RedHat/Fedora distributions of Linux since 1995. I typically keep my home machines running a fairly recent release. I find that it’s easier to upgrade if I don’t procrastinate through too many releases.

On the other hand, I’ve found that upgrading too soon can be risky. I depend on third party repositories for some of the software that I use (e.g. an ntfs driver). It takes between two to four weeks before the software repositories start offering their packages for a new distribution.

If I wait at least a few weeks to upgrade, after the release of the new distribution, and I run into problems, I can usually google to find a solution to the problem. If I’m on the bleeding edge, I don’t get that benefit. Instead, I’m the one posting problems and solutions that other people google.

On Monday, I downloaded the recently released Fedora Core 5 DVD via bittorrent, and decided to upgrade my less-critical Fedora Core 3 machine.

Backup. Even though I’m generally careful, I find that it’s easier to recover from a mistake if I have a complete backup. For this, I used Norton Ghost.

First try: I was impressed by the shiny new graphics in the installer. After several screens of questions and after it analyzed my system to figure out what packages to upgrade, it informed me that I didn’t have enough disk space (I only had 2 Gig of free space). The install aborted and I had to reboot my machine.

Yum cache: I use yum to upgrade my machines, and I happen to know that by default, it leaves a cache of the packages in the /var/cache/yum directory. I deleted the directory, which freed up 2 Gig of space. Shouldn’t the installer do that for me?

Second try: The installer ran without a hitch. It upgraded my system, even though it took a while.

First boot: The boot process hung when it tried to initialize OpenCT smart card terminals, whatever those are. I don’t think I have any. Back in the days when Iinstalled FC3, I had to add “acpi=off” and “pci=noacpi” to the boot loader before FC3 would work on my system. The FC5 upgrade had left those options in place. I deleted the options, and rebooted. This time, the boot process didn’t hang. Wierd. There may not have been a correlation.

First login: The GNOME desktop loaded much more quickly than with FC3. However, several error dialogs appeared. Various resources couldn’t be located, including icons for desktop launchers that I had customized. As I already mentioned, the third party repositories that I use with yum didn’t have FC5 packages available.

Upgrade versus Fresh Install: I find that upgrades are less than ideal, especially when I want to experience the new features of a distribution. Upgrades tend to leave out new features and new packages. Since RedHat has been changing SELinux policices at a rapid rate, an upgrade isn’t likely to leave SELinux in a workable state. A fresh install is better. For a home, desktop system that isn’t a server, it’s probably best to disable SELinux. It will be interesting to see how SELinux fares compared to the now open-source AppArmor that is included with SUSE. AppArmor appears to be easer to use and configure, but SELinux has fewer gaps in security coverage. I tend to think that ease-of-use will win out. In any case, I do use SELinux to protect one of my web servers.

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Run time linker and library symbols

Did you know that almost all programs are incomplete until you start them? When programmers compile a program, it is only partially complete. When you start a program, the operating system looks at the program and runs another program to make it complete — called a run time linker. In the case of modern Linux, it’s usually /lib/ld-linux.so.2. Read the manpage on ‘ld.so‘ for more information.

  • You can find out what libraries your program uses with ldd /path/to/program. You can also run it as follows (assuming you’re using bash/ksh/zsh): LD_DEBUG=files program
  • Find out what symbols a program uses and from which shared libraries: LD_DEBUG=bindings program
  • Have you ever wanted to find out what shared library contains the code or definition for a function or symbol? David Wheeler shows how you can find it: nm -o /lib/* /usr/lib/*/* | grep symbol_name Then look for the capital “T”. Read the Program Library HOWTO by David Wheeler.
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Linux versus Solaris

Here are some reasons why I like Linux better than Solaris:

  • Easier to use. Linux is pre-configured with user-friendly defaults compared to Solaris 10.
  • Better desktop support. In Fedora Core, or in SUSE, I can insert a USB flash drive, and it automatically appears on my desktop. Not so with Solaris 10.
  • Default shell is bash. Much better than vanilla ‘sh’.
  • Good aliases including ‘ll’
  • Good default command-line prompt.
  • Fantastic GNU command line and console programs
    • tar -zxvf whatever.tar.gz
    • find … -print 0 | xargs -0 …
    • vim
  • Root’s shell is bash, and the home directory is /root instead of /
  • Linux configuration utilities are more plentiful and easier to use.
  • Gnome is far better on Linux. The Sun “Java Desktop” (Gnome renamed), is an improvement over CDE, but is not even close to mainstream Linux distributions in terms of ease of use and features.
  • More knowledge “in the wild” for Linux than for Solaris. Easier to find support for Linux using Google.

Solaris is my favorite commercial UNIX. I prefer it over AIX, HP-UX, etc.