Fri, 19 Aug 2011

How to read ftp-masters package numbers table

In my previous blog about Debian's growing archive size I pointed as reference to an hard to read table on the ftp-master server, and missed that the table is not self explanatory and on the first glance hard to read.

The table currently looks like the following:

               |  e   |  s   | p-u  |  t   |  u   |t-p-u | l-r  | s-u  |  o   |o-p-u | s-r  |
---------------------------------------------------------------------------------------------
     all       | 1096 |12034 |   70 |14442 |15784 |   20 |    1 |   12 | 8910 |  230 |    0 |
    alpha      |    - |    - |    - |    - |    - |    - |    - |    - |13183 |  297 |    - |
    amd64      | 1164 |16997 |  242 |18581 |19605 |   39 |    - |   21 |13964 |  342 |    - |
     arm       |    - |    - |    - |    - |    - |    - |    - |    - |13251 |  291 |    - |
    armel      |  988 |16401 |  239 |17879 |18680 |   39 |    - |   21 |13411 |  327 |    - |
     hppa      |    - |    - |    - |    - |    - |    - |    - |    - |13227 |  264 |    - |
  hurd-i386    |  445 |    - |    - |    - |12622 |    - |    - |    - |    - |    - |    - |
     i386      | 1178 |17188 |  242 |18727 |19751 |   39 |    - |   21 |14377 |  350 |    - |
     ia64      |  951 |16036 |  239 |17303 |18045 |   39 |    - |   21 |13554 |  329 |    - |
kfreebsd-amd64 |  807 |14499 |  231 |15905 |16480 |   39 |    - |   21 |    - |    - |    - |
kfreebsd-i386  |  826 |14491 |  231 |15881 |16498 |   39 |    - |   21 |    - |    - |    - |
     mips      |  974 |16269 |  241 |17730 |18504 |   39 |    - |   21 |13638 |  323 |    - |
    mipsel     |  984 |16291 |  239 |17807 |18558 |   39 |    - |   21 |13600 |  319 |    - |
   powerpc     | 1078 |16677 |  239 |18156 |19036 |   39 |    - |   21 |13872 |  332 |    - |
     s390      | 1030 |16252 |  239 |17678 |18469 |   39 |    - |   21 |13331 |  327 |    - |
    source     |  522 |14974 |   51 |16376 |17405 |    1 |   19 |    6 |12519 |   75 |  151 |
    sparc      |  992 |16423 |  239 |17895 |18673 |   39 |    - |   21 |13542 |  329 |    - |

The lines represent different hardware architectures Debian supports, like amd64 (for 64-Bit PCs), i386 (for 32-Bit PCs), etc. Two lines are kind of special, the one marked source and the one marked all. Let's start with the source line: That counts the number of source packages. Those are rarely seen by end users. Source packages contain the actual source needed to build a package, as well as Debian specific changes and a blue print on how to create an actual installable binary package from the source.

As you can see Debian supports quite some architectures, which leads to a small problem on the mirrors: Quite a lot shipped in Debian is actually architecture independent. For example documentation, most sound and graphic files, or level data for a game. To avoid storing the very same date multiple times, Debian makes haeavy use of so called arch: all packages. You might have noticed them already while installing them:

Hole:5 ftp://ftp.rrzn.uni-hannover.de/debian/debian/ squeeze/main extremetuxracer-data all 0.4-4 [28,1 MB]
Hole:6 ftp://ftp.rrzn.uni-hannover.de/debian/debian/ squeeze/main extremetuxracer amd64 0.4-4 [273 kB]

In this example I installed a quite small game on the amd64 architecture, which depends on a quite big architecture independent package (notice the all between package name and version) containing it's data.

But what column to pick?

The columns represent so called suites. The s is for stable, currently Debian 6.0 aka Squeeze and o for oldstable, aka Debian 5.0 Lenny. The t is for testing, aka Wheezy or the upcoming Debian 7.0. The u is for unstable aka sid. The e is for experimental, used for stuff probably not yet ready to be part of a stable release and therefore not uploaded to unstable. The rest is not that interesting (as you see it's mostly empty anyway), like s-u for stable updates, several p-u suites for proposed-updates (that is stuff that might end up in the next point release, and should be tested). And then we have s-r and l-r which I forgot what they are about... Sorry.

But back to topic: As I explained briefly a source package is mostly used internally, but may create several binary packages, which a user can install. So the most interesting number for users is the number of binary packages on an arch. So we usually publish this number. So for example, using squeeze on i386 you can install: 17'188 (architecture dependent packages, column s row i386) + 12'034 (architecture independent packages columns s row all) = 29'222 packages. And for completeness: They are build from 14'974 source packages (row source column s).

So if look that up for unstable on amd64 you should get to the result 35'389 binary packages build from 17'405 source packages. Slightly less than I reported yesterday, because we removed some old stuff e.g. obsolete libraries in the meantime.

Update: Jörg just explained me, that the s-r and l-r are there to ensure Debian complies with the GPL. They hold the sources of everything shipped in the original lenny and squeeze releases.

Update 2: Jörg explained it to me again: s-r and l-r contains sources used without being referenced by a package, and so might get lost otherwise. One example is the kernel used by the debian installation system. You have to boot a kernel somehow, so it can't be packaged. But we still need to save the sources, so it is referenced in these suites and won't get lost.

postet at 13:33 into [Debian] permanent link