Raphaël Hertzog: People behind Debian: Maximilian Attems, member of the kernel team
Maximilian, along with the other members of the Debian kernel team, has the overwhelming job of maintaining the Linux kernel in Debian. It s one of the largest package and certainly one where dealing with bug reports is really difficult as most of them are hardware-specific, and thus difficult to reproduce.
He s very enthusiastic and energetic, and does not fear criticizing when something doesn t please him. You ll see.
My questions are in bold, the rest is by Maximilian.
Who are you?
My name is Maximilian
Attems. I am a theoretical physicist in my last year of PhD at the
Technical University of Vienna. My main research area is the early phase of a
Quark-Gluon Plasma as produced in heavy ion collisions at the LHC at CERN. I am
developing simulations that take weeks on the
Vienna
Scientific Cluster (in the TOP 500 list). The rest of the lab is much less fancy and boils down
to straight intel boxes without any binary blobs or external drivers (although
lately we add radeon graphics for decent free 3D). Mathematica and Maple are
the rare exceptions to the many dev tools of Debian (LaTeX, editors, git,
IDE s, Open MPI, ..) found at the institute, as those are unfortunately yet
unmatched in Free Software for symbolic computations. The lab mostly runs a
combination of Debian stable (testing starting from freeze) for desktops and
oldstable/stable for servers. Debian is in use for more than 10 years. So
people in the institute know some ups and downs of the project. Newcomers like
my room neighbors are always surprised how functional a free Debian Desktop
is. 
What s your biggest achievement within Debian?
Building lots and lots of kernels together with an growing uptake of the officially released linux images.
I joined the Debian kernel team shortly after Herbert Xu departed. I had been
upstream Maintainer of the linux-2.6 janitor project for almost a year brewing
hundreds of small cleanups with quilt in a tree named
kjt for
early
linux-2.6. In Debian we had lots
of fun in sorting out the troubles that the long 2.5 freeze had imposed:
Meaning we were sitting on a huge diverging monolithic semi-good patchset.
It was great fun to prepare 2.6.8 for Sarge with a huge team enthusiastic in
shipping something real close to mainline (You have to imagine that back then
you had no stable or longterm release nor any useful free tools like git. This
involved passing patches around, hand editing them and seeing what the result
does.)
From the Sarge install reports a common pattern emerged that the current Debian
early userspace was causing lots of boot failures. This motivated
me to develop an alternative using the new upstream initramfs features. So I got
involved in early userspace. Thanks to large and active development team
initramfs-tools got a nice ecosystem. It still tries to be as generic and
flexible as possible and thus gains many nice features. Also H. Peter Anvin
(hpa) gave me the official
co-maintenance of klibc. klibc saw uptake and good patches from Google
in the last 2 years. I am proud that the early userspace is working out
fairly well these days, meaning you can shuffle discs around and see your box
boot.
Later on we focused on 2.6.18 for Etch, which turned out to a be good release
and picked up by several other distributions. Only very much later
we would see such a sync again. With 2.6.26 for Lenny we got somehow
unlucky as we just missed the new longterm release by one release.
We also pushed for another update very late (during freeze) in the release
cycle, which turned out to semi-work as too much things depend on linux-2.6.
For Squeeze 2.6.32 got picked thanks to discussions at Portland Linux Plumbers
and it turned out to be a good release picked up by many distributions and
external patchsets. The long-term support is going very well. Greg KH is doing
a great job in collecting various needed fixes for it. Somehow we had hoped
that the Squeeze freeze would start sooner and that the freeze duration would be
shorter, since we were ready for a release starting from the actual freeze on.
The only real big bastard on the cool 2.6.32 sync is Red Hat. Red Hat
Enterprise 6.0 is shipping the linux-2.6 2.6.32 in obfuscated form. They
released their linux-2.6 as one big tarball clashing with the spirit of the
GPL. One can only mildly guess from the changelog which patches get applied.
This is in sharp contrast to any previous Red Hat release and has not yet
generated the sharp and snide comments in press it deserves. Red Hat should
really step back and not make such stupid management moves. Next to them
even the semi-maintained Oracle Unbreakable 2.6.32 branch looks better:
It is git fetchable.
What are your plans and those of the kernel team for Debian Wheezy?
Since 2.6.32 many of the used patches landed upstream or are on the way
(speakup, Kbuild Debian specific targets, ..). The proper vfs based unionfs is
something we d be looking forward. We haven t yet picked the next upstream
release we will base Wheezy on, so currently we can happily jump to the most
recent ones. There are plans for better interaction with Debian Installer
thanks to generating our udebs properly in linux-2.6 source itself. Also we
are looking forward to using git as tool of maintenance. We d hope that this will
also allow for even better cross distribution collaboration.
Concerning early userspace I plan to release an initramfs-tools with
more generic userspace for the default case and finally also a klibc
only for embedded or tuning cases.
What do you like most in Debian?
For one thing I do like the 2 year release cycle. It is not too long to have
completely outdated software and on the other hand it gives enough time to
really see huge progress from release to release. Also at my institute the
software is is recent enough without too much admin overhead. For servers the
three years support are a bit short, but on the manageable side.
I do enjoy a lot the testing distribution. For my personal use it is very stable
and thus I mainly run testing on my desktop and work boxes. (Occasionally
mixing in things from sid for unbreaking transition or newer security fixes).
Debian is independent and not a commercial entity. I think this is its main
force and even more important these days. I enjoy using the Debian platform a
lot at work thus in return this motivates me to contribute to Debian itself. I also like the
fact that we strive for technical correctness.
Is there some recurrent problem that hinders the progress of Debian?
The New Maintainer process is a strange way to discourage people to
contribute to Debian. It is particularly bureaucratic and a huge waste of time
both for the applicant and his manager. It should be completely thrown
overboard.
One needs a more scalable approach for trust and credibility that also enhances
the technical knowledge for coding and packaging of the applicant.
NM is currently set in stone as any outside critics is automatically rejected.
Young and energetic people are crucial for Debian and the long-term viability of
the project, this is the reason why I d consider the New Maintainer process
as Debian s biggest problem.
Note from Rapha l Hertzog: I must say I do not share this point of view on the New Maintainer process, I have witnessed lots of improvements lately thanks to the addition of the Debian Maintainer status, and to the fact that a good history of contribution can easily subsume the annoying Tasks & Skills questionnaire.
Another thing I miss is professional graphics input both for the desktop
theme and the website. I know that effort has been done there lately and
it is good to see movement there, but the end result is still lacking.
Another trouble of Debian is its marketing capabilities. It should learn to better sell itself. It is the distribution users want to run and use not the rebranded copies of itself with lock-in sugar . Debian is about choice and it offers plenty of it: it is a great default Desktop.
Linus Torvalds doesn t find Debian (and/or Ubuntu) a good platform to hack
on the kernel. Do you know why and what can we do about this?
The Fedora linux-2.6 receives contributions from several Red Hat employed
upstream sub-Maintainers. Thus it typically carries huge patches which are not
yet upstream. As a consequence eventual userland troubles get revealed quite
quickly and are often seen there first. The cutting edge nature of Fedora
rawhide is appealing for many developers.
The usual Debian package division of library development files and the library
itself is traditionally an entry barrier for dev on Debian. Debian got pretty
easily usable these days, although we could and should again improve a lot
more in this sector. Personally I think that Linus hasn t tried Debian
for years.
I have the feeling that the implication of the Debian Kernel team in LKML
has been on the rise. Is that true and how do you explain this?
Ben Hutchings is the Nr.1 contributor for
2.6.33.
He also is top listed as author of patches on stable
2.6.32.
Debian is not listed as organization as many send their linux-2.6 patches from
their corporate or personal email address and thus it won t be attributed to
Debian.
There is currently no means to see how many patches get forwarded for
the stable tree, but I certainly forwarded more then fifty patches.
I was very happy when Greg KH personally thanked me in the
2.6.32.12 release.
In the Squeeze kernel, the firmwares have been stripped and moved into
separate packages in the non-free section. What should a user do to ensure
his system keeps working?
There is a debconf warning on linux-2.6 installation. It is quite clear
that the free linux-2.6 can t depend on the firmware of the non-free
archive (also there is no strict dependency there technically).
On the terminal you d also see warnings by update-initramfs on the
initramfs generation for drivers included in the initramfs.
The debconf warning lists the filename(s) of the missing firmware(s). One can then apt-cache search for the firmware package name and install it via the non-free repository. The check runs against the current loaded modules. The match is not 100% accurate for special cases as the one where the device might be handled well by this driver without firmware, but is accurate enough to warrant the warning.
The set of virtualization technologies that the official Debian kernel
supports seems to change regularly. Which of the currently available
options would you recommend to users who want to build on something
that will last?
KVM has been a smooth ride from day zero. It almost got included instantly
upstream. The uptake it has is great as it sees both dev from Intel and AMD.
Together with libvirt it s management is easy. Also the performance of virtio is
very good.
The linux containers are the thing we are looking forward for enhanced chroots
in the Wheezy schedule. They are also manageable by libvirt.
Xen being the bad outside boy has an incredible shrinking patchset,
thus is fair to expect to see it for Wheezy and beyond. For many it may
come a bit late, but for old hardware without relevant CPU it is there.
Many tend to overstate the importance of the virtualization tech. I d be much
more looking forward to the better Desktop support in newer linux-2.6. The
Desktop is important for linux and something that is in heavy use. The much
better graphics support of the radeon and nouveau drivers:
- For Nouveau in 32 with 33 drm we could only deliver a first taste meaning something better then rusty nv.
- For Radeon the support for Evergreen and newer is only been shaping now.
Thank you to Maximilian for the time spent answering my questions. I hope you enjoyed reading his answers as I did. Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Twitter and Facebook.
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