SL5 in DAMTP

Scientific Linux (SL) is a Linux system put together by Fermilab, CERN, and various other labs and universities around the world. It is a Linux system with additions which are mostly aimed at use in the Scientific Community.

In DAMTP the default desktop Linux setup was, until 2007, based on Scientific Linux 3.0.8 (SL308). During 2007 we upgraded all the machines to Scientific Linux 5.0 (SL50) - after a testing period of about a month for users to check that most things worked.

Since then we have upgraded through various minor versions and currently we are running Scientific Linux 5.7.

This set of pages is intended to document the differences between SL308 and SL50 for those who didn't get a chance to try the test machines, and list any known problems or omissions in the version being installed.

Why are we upgrading?

There are a number of reasons to update the default desktop Linux setup including:

  • Many users expect newer versions of packages than we had
  • New computers which work with the old system are getting harder to find (hardware not supported)
  • Commercial packages are starting to expect newer systems e.g. the latest Matlab (R2007a) will not run on SL308 - it does work on SL50
  • Support for the old system will eventually end and there will be no further (security) updates at all

We understand that some people won't want anything to change so we have attempted to configure things to minimise changes - as much as we can.

Scientific Linux 5.7 is currently the latest version. We have been using sl5 since early in 2007 working on making it ready for use in DAMTP -- adding locally built extra packages and configuring things to inter-operate fully with the existing systems.

It was important to have the new system tested by people other than computing support staff to ensure we had not forgotten anything significant. A number of key changes were made because of feedback - including the addition of a number of packages we had missed!

GNOME settings

In SL5x the version of Gnome is quite different and so if it sees settings made by SL3xx it will get confused -- showing the wrong menus and panel items.

To avoid this being a big problem we added checks (during login) for older Gnome settings and offer to move them out of the way. If old Gnome setting are detected you will see something rather like:

Gnome settings are old warning

If you agree your existing settings will be moved into a directory OLD-Gnome-Settings/<current-date>/ and the session will be started with the new SL5x defaults. If you do this while running a Gnome session on an SL3xx machine it will probably get very confused!

The tests used to detect old Gnome settings are not foolproof. Please let us know if it guesses wrong - especially if it thinks that settings are old when they are not.

Using a mixture of SL3xx and SL5x systems with Gnome is likely to cause utter confusion, which is why we upgraded all systems to SL5 as quickly as possible.

Now the last few SL3xx systems are about to be turned off - they are only providing some older services - none are on desks.

KDE settings

As far as we can tell with small amounts of testing the KDE session settings do not need special action for this update. Please report any problems in case it turns out we are wrong.

DAMTP-session (FVWM) settings

The version of fvwm is identical (this is locally added anyway), so should behave the same as it did on our previous Linux setups.

Note that for some time Gnome has been the default session type in DAMTP, and while the old DAMTP session (which uses fvwm) is still available in SL5x it may be removed in some future update.

While the version of twm has changed it appears to behave just like the old version.

Highlights of SL50

There is a new Gnome setup which significantly alters the default Desktop environemnt. A greatly updated KDE is present for those who prefer that environment.

The updated graphical login manager now stores the user's default session information in a different place so unless another session type is chosen it will default to the Gnome for the login session.

Many core programs, utilities and libraries are updated to much more recent versions, and it uses a vastly newer Linux kernel.

Details of some of the updates and other changes can be found on the SL5 in DAMTP - details page.

The new Gnome session defaults puts the menus at the top of the screen rather than the bottom, and now has three menus Applications, Places and System. The DAMTP additions to the menus and panels are now slightly different too.

The KDE session looks fairly similar to the old one though the details of the default contents of the menus and Kicker are somewhat different.

Under both Gnome and KDE sessions removable media (Floppy, CDs, USB devices etc) are automatically mounted and will appear on the Desktop. Those not using Gnome or KDE can get a window displaying a graphical view including the removable and hot-pluggable devices by running:

     nautilus --no-desktop computer:/

though that won't draw the images/icons on the Desktop.

The login-screen looks a bit different, here is a (quarter-resolution) image of the GDM login-screen of deldel.damtp.cam.ac.uk (note that this looks closer to our existing SL308 login screen than to the SL50 default!):

DAMTP SL50 Login screen

and here is a fairly random image (quarter-resolution) of a test user logged in with the new Gnome setup:

Using Gnome under SL50

Note that that isn't using the default desktop background - we have added some extra desktop background images including that one!

Does anyone have any good images we can/should add to the default install?

Here are some more (hopefully relevant) screenshots of parts of the default Gnome session:

Main Gnome Applications menu:

Gnome Applications menu

Gnome DAMTP apps menu:

Gnome DAMTP apps menu

Screen fragment showing Gnome menus, panel defaults and part of the desktop:

Gnome menus and panel defaults

Things we know which are broken - or at least somewhat different:

  • mtools access to USB devices, Gnome (and KDE) users now will have USB (and CD/DVD) devices mounted automatically. Command line options exist but are not very nice to use.
  • kpdf is apparently not a very good PDF viewer though the gnome 'document viewer' evince mostly works (for several formats - not just PDF), but we have also added xpdf (an updated version in fact) for those who prefer it.
  • g77/f77 have been replaced by the newer gfortran which also supports the fortran-9x standard. The new gcc (4.1.1) is the default compiler. We do have the compatability gcc-3.4 compilers installed (gcc34, g++34) for those who need to compile code to link against older libraries etc. The compatability g77-3.4 compiler is installed but must be called as g77-34 rather than just g77. Anyone running g77 or f77 should get a warning message telling them to use gfortran instead. This is intended to remind those who have got used to typing f77 (or g77) and catch uses in Makefiles and scripts.

Please let us know if you find anything else which does not work properly.

What can/will be changed after deployment?

Bugfixes to the scripts and configurations will be applied as we find/fix problems. Please report odd behavious - we may not have seen it before. Security updates for packages will be applied as we get them, some of these may require reboots - as before.

We will consider adding packages that are not currently installed. Especially if they are independently requested by several people and the packages ship as a standard part of Scientific Linux 5.x. See the standard set of packages (for i386) in the directory:

   /opt/instsl/upstream/56/i386/SL/

and are also available for viewing by web browsers at http://www.damtp.cam.ac.uk/linux/scientific/56/i386/SL/ as well as from many other mirrors. Most of the extra DAMTP added packages are available for download from http://www.damtp.cam.ac.uk/linux/sl/damtp/5x/ though be careful about using them elsewhere since some have DAMTP specific patches or configurations.

Please let us know if we have missed any packages you really need. We may not be able to have them installed right away but we will certainly add them to a lits to be tried.