Hi all,

I've done a lot of searching, but I still haven't found a clear-cut description of the major differences between the 2.4 and 2.6 kernel series.

From what I've read, 2.4 uses Hotplug to find things like USB drives and PCMCIA cards while 2.6 uses UDEV. What's the difference and is UDEV really better than Hotplug?

After I tweaked my fstab, I was able to manually mount my USB drive, CD-ROM burning drive, and DVD-ROM drive with the 2.4 kernel from the default Slackware 11 installation.

What other differences are there between the two, and what advantages does the 2.6 kernel have over the 2.4?

Thanks,

-Drew

Hi,

Maybe you should read the Slackware 11 RELEASE_NOTES.

You will get PV's statement on the issue of 2.4 vs 2.6 for Slackware 11.

You could read the Slackware 12 UPGRADE.TXT to get a understanding for the upgrade from 11 to 12. I would suggest a fresh install from cdrom fro 12 vs upgrade. My reason for this is suggestion is if you plan on doing a change in your system or wish to use the new 2.6 kernel. Then use the 12 RC1.

Look at my post 'Slackware LQ Suggestions!' to get some good links for 12 RC1.

you really are a traditionalist, eh?

there are literally thousands manyears put into 2.6...

maybe http://kernelnewbies.org/LinuxChanges is helpful


.
udev vs. hotplug: yes
performance: it depends. i heard under some database loads 2.4 features better results

new features/drivers are only added to 2.6

Thanks for the responses, guys.

I read the release notes when I first installed Slackware 11 after it was released last year. However, beyond Pat V's opinions on the stability of the 2.4 kernel versus the 2.6 kernel, there's not a lot of information there.

I'm not a traditionalist, I just started using Linux last year! But the 2.4 kernel is the default for Slackware 11, Pat V says it's very stable, so that's what I chose.

Perhaps if I phrase my question differently it will help:

What does the 2.6 kernel do that the 2.4 kernel can't? Or, how is the 2.6 kernel an improvement?

I think I get the Udev versus Hotplug issue, but what else is there?

Thanks,

-Drew

Well, it has much better support for a lot of stuff ... especially all things SCSI. (mostly USB, etc.)

There are many changes at many layers: Many new drivers (but a few which aren't there anymore). Much improved power-management. Many changes to improve and ease support of non-386+-based architectures. Much more revised SMT, SMP and NUMA support. Support for REAL Threads (NPTL). Many brand-new syscalls. The famous O(1) scheduler. And so on...

As for the hotplug-vs-udev thing, Linus on his recent rant about the status of suspend/resume seemed to prefer how hotplug worked.

The main problem some people (and I) have with the 2.6 kernel is that there are usually too many (>1) major changes merged between releases, which tends to cause stability issues (as has been acknowledged by the 2.6 mantainer, Andrew Morton) and also reintroduces old bugs. Linus has taken measures against this, and since the .20 release there's been a lot of tracking on regressions and bugs before the release, so the situation seems to be improving over time (I've found .21 to be very stable, for example).

Theoffset,

Thanks for the very informative response and for the links!

From what I understand, if I were using relatively modern hardware (I'm not), then I would definitely want a 2.6 kernel. Otherwise, it's a toss-up with laptop users seeming to prefer a 2.6 kernel.

I'll likely keep the 2.4 kernel on my seven-year-old desktop, but probably install a 2.6 kernel on my five to six-year-old laptop. I've got OpenSUSE 10.2 on it now, but I'm thinking of installing Slackware 11 -- or waiting until 12 comes out and installing that instead.

Regards,

-Drew