On Wed, 24 Oct 2007 12:47:40 -0700
"Clark, Douglas" <[EMAIL PROTECTED]> wrote:

> I am reading an article in the Oct 22, 2007 edition of InformationWeek
> titled "The Relentless Pace of Linux" on page 43.  The article makes a
> reference to "Kernel 2.6.23" and I am trying to make some sense of that
> identification to what I am running.
>
> On my server running SLES 9 i386 when I issue a "uname -r" command the
> following is returned "2.6.5-7.287.3-default."
> When I issue the same "uname -r" command on the mainframe LPAR I receive
> the following "2.6.5-7.287.3-s390x."
>
> How do those versions map back to the statement "Kernel 2.6.23?"

2.6.5-7.287.3 is the SLES kernel RPM package version.

Red Hat ones look similar - eg I've got 2.6.22.1-41.fc6 on one box

The first bit is the kernel major version

0.x was the early development kernels
1.x were the first "production" grade kernels
2.x was when we went to version 2.* (because Linus felt like it in part
and also because it went multi-architecture)

The x is then odd for development and even for the production

so 2.0 was production, 2.1 devel, 2.2 production etc

There are currently no plans for major changes needing a seperate 2.7
development tree. 2.6 is the current production kernel

Ok so we've got to 2.6

The next bit is the release. We (the community) crank out several releases
a year each one of the form 2.6.n where n was 0, 1, 2 , ... with release
candidates of the form 2.6.n-rc1/rc2/rc3/...

So 2.6.5 is the fifth release of 2.6 from way back when. 2.6.23 is the
latest release, and 2.6.24-rc1 is what people are fixing up now.

After 2.6.23 appears there may be 2.6.23.1 2.6.23.2 etc with minor
backport fixes from 2.6.24-rc as they are found and considered important.
Unlike enterprise kernel products the upstream community tree usually
stops doing 2.6.22.x once 2.6.23 is out.

After the "-" you've got RPM specific information which will tell you
things about the package but are really vendor and packaging method
specific. (eg the .fc6 on Red Hat is 'Fedora 6')

There are lots of these package versions as enterprise vendors take the
base kernel, they brutalise it with things like oracle test suites,
netbench, validation suites of all kinds and tune and adjust as needed.
They also select important fixes from the later releases and backport
them into their kernel with the goal of maximising stability by picking
out fixes but avoiding big changes and higher risk updates from later
releases.

Over time customer and vendor found bugs, security reports and further
bug fixes from upstream get merged into the enterprise vendor trees again
trying to maximise the reliability and this all gets reflected somehow in
the changing numbers after the "-"

For non-enterprise products its often quite a different process but with
the same kind of numbering approach. A typical Fedora Linux kernel is the
latest upstream kernel + minor important fixes from the next -rc. It will
change versions during the release and the emphasis is on trying to be
stable but provide new features unlike the rather harder and more work
done for the enterprise 'risk averse' habit of backporting fixes.

Alan

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