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Revision as of 08:54, 16 February 2011

Data Layers

For the data the layering is slightly different. The data layers are relevant from the users view and the model may help when designing UIs.

  • Layer 0: Source packages
  • Layer 1: Packages
  • Layer 2: Applications
  • Layer 3: Groups
  • Layer 4: Repositories and Products
  • Layer 5: Repository Registry (Does not exist yet)

Layer 2: Applications

Right now "applications is basically just a sub set of packages that have been selected as "interesting for the user to install". Typically this excludes libraries and development packages (although they are interesting to install for developers) but includes services that might be selected by hand like web servers.

The AppStream project aims for making this layer more rich by actually adding informations to the packages selected.

Layer 3 Groups

There is some confusion in the Fedora/Red Hat world what a group is as the same term and data structure is used for two things:

  1. Categories to put applications in (putting together similar applications)
  2. Creating a entity that can be installed at once providing a larger scale functionality (putting together one of each kind)

For the scope of this layering we will probably still need to divide these two into separate layers.

Layer 4 Repositories

The community distributions are aiming at making the need for this layer to go away. Especially Fedora has an attitude of telling the users that their own repositories are the only once to be used. IN an enterprise environment it might be desirable to have a large number of 3rd party repositories as a way for 3rd part vendors to offer their software.

Layer 5 Repository Registry

As far as I know such thing does not exist right now. In a world of lots of repositories this might be necessary but we are not in this world.

Orders of Magnitude

The data layers are true abstractions of the underlying ones. Which means that the number of entities are getting smaller to the top (with exception of Layer 0):

Layer Entities in Distributions
Community Enterprise Installed
0 Source 10k 2k -
1 Packages 20-30k 3k 1-2k
2 Applications 2k 1k (?) 100?
3 Groups 30-100 30-100 10
4 Repositories ~5 (?) 1-3