April 17, 2014

Don't Trip on the Red Carpet, Evolve with GNOME CVS - page 2

A Good Week for Compulsive Updaters

  • February 23, 2001
  • By Michael Hall
So, at long last, down to the big item for the week which is Red Carpet.

People who have been downloading and using Ximian's GNOME desktop distribution for a while are pretty familiar with both the GUI installer and update tool Ximian uses to ease acquisition of their software. Red Carpet is the next generation of these tools, designed to not only make getting the basic desktop easier but providing an easy-to-use method for handling all packages on a given machine. In addition, Red Carpet will eventually be used to deliver commercial software from Ximian partners.

Getting Red Carpet
Red Hat 6/7 users can get Red Carpet via the current Ximian Updater by pointing it at the Red Carpet mirror. Debian users can add the following line to /etc/apt/sources.list:

deb ftp://spidermonkey.ximian.com/pub/red-carpet/binary/debian-22-i386/ ./

Keep in mind that installation of Red Carpet will, for the moment, break current snapshots of Evolution you may have on your machine, requiring installation of gtkhtml as detailed earlier in this column.

Red Carpet expects to find either Red Hat 6/7 or a Debian system in place. It didn't work on a Progeny Debian machine, which is based largely on Debian's Woody release, but did work on a Potato-based system.

Channel Surfing
Red Carpet describes the groupings of packages it presents as "channels". Users can subscribe to several possible channels at this point. On a Debian machine, the available channels included the Ximian GNOME desktop, Evolution snapshots, the Red Carpet release itself, and the Debian archives.

By subscribing to a channel, users can keep abreast of a specific project or collection of files. Once subscribed, Red Carpet downloads status information on the packages in a given channel at startup and notifies users of how many updates exist and how large a download they represent.

The channel concept is handy because it gives Red Carpet a certain level of versatility. It's possible to settle for simple package management for a vanilla installation by subscribing only to the basics, such as Ximian's GNOME desktop and the distribution's basic archive. For users who feel like following projects under heavy development, such as Evolution, adding a channel for that project makes for a painless way to keep up with the project without missing out on the latest developments because they're buried in with the more mundane basic packages. On the flipside, all those interesting bleeding-edge projects won't distract from the potentially more important business of keeping track of security updates and bug fixes for essential packages.

Using Red Carpet
Upon selecting a channel, users are presented with install and remove options. Selecting the install option presents a list of all the available packages in a given channel. The list is cleanly presented, showing the package name, the available version, and its size. In the preferences, there's a very nice option for selecting "pretty package names." Ximian has taken the time to provide easy-to-understand names for many packages with sometimes-obscure names. "xsane" for instance, changes to "Graphical Scanner Program (xsane)" under the naming scheme.

In addition to the clearer package names, a small information icon can be clicked by each package that presents a more verbose description of what the package does.

After the user selects packages for installation, Red Carpet presents a screen that provides some information on the downloads required. In addition to delivering the packages, Red Carpet also tracks and draws in any package dependencies and handles conflicts by notifying the user of any required removals. This is similar in practice to Debian's dselect or apt-get, or tools like gnorpm, but the process is much simpler than dselect (since there are fewer options) and presents a little cleaner interface than gnorpm. Red Carpet also takes the additional hand-holding step of warning that removing packages is a sometimes-risky proposition.

Getting the file for installation involves four stages:

  • Downloading
  • Verifying
  • Installing
  • Configuring
During download, users who access the 'net via modem or working in similarly bandwidth-constrained situations have the option to pause the file transfer. According to Ximian, it's possible to pause the download and disconnect from the 'net entirely in order to place a phone call, for instance, and then reconnect and resume the transfer.

The verification stage allows Red Carpet to compare cryptographic signatures on the packages to ensure they come from a reliable source, and it offers a warning if a package is unsigned/unverifiable. The usefulness for this in eventual commercial applications seems clear.

The installation and configuration stages involve unpacking the files in question and presenting dialog boxes for any configuration options. When I installed the gnome-pilot package, for instance, was presented with a small window prompting for the serial port on which our Pilot was connected.

Uninstalling packages was also simple: users select which packages should come off the system, Red Carpet checks for broken dependencies and handles the removal.

In addition to adding and removing packages and summarizing availability, Red Carpet offers a "news" page that provides brief headlines and information from Ximian which are downloaded at startup. The news page could turn Red Carpet into a really useful conduit for information about what's going on with Ximian and GNOME in general if Ximian chooses to keep the news feed updated. The thought of being able to check in on the latest by firing up a relatively small application as opposed to a full-blown web browser is a pleasant one, especially since that application then provides a streamlined means to acting on the information by downloading new stuff or updating existing packages on the spot.

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