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Re: concurrent installs of previous + current kernels



In <01B9C640-493C-4D1B-BA0F-20AED4B20EAE@sonous.com>, Lev Lvovsky wrote:
>On Feb 1, 2010, at 3:13 PM, Boyd Stephen Smith Jr. wrote:
>>> This is totally understandable for most package installs, however with a
>>> kernel, keeping the previous version installed is useful (obviously).
>>
>> It's usually not a big deal when the kernel ABI hasn't changed.
>>
>> If you have a strong desire to keep every kernel version around, you'll
>> have to go outside the official packages.  From what I understand, the
>> Debian provided tools to build kernel packages can handle this easily, but
>> I've not tried it myself.
>
>Well, currently the only desire I have is to keep the version of the kernel
> which I currently have installed, as well as whatever debian has available
> as the "latest".  If I understand, this requires that I build each of these
> kernels?

New upstream versions, or any version that changes the kernel ABI will be 
retained (or at least can be simply retained), since the kernel ABI will be in 
the new package name--it is a replacement only as far as relatively weak 
dependencies are concerned.

For example, your Lenny kernel will be retained when/if you get a kernel from 
Squeeze (e.g. during a release-time upgrade).  You can install the Lenny, 
Squeeze and Sid kernels side-by-side with some ease currently.

If there is a Lenny-and-a-half "release", it might have a kernel with a new 
ABI.  (The Etch-and-a-half "release" did.)  If that is the case, installing 
the "Lenny-and-a-half kernel" and the "Lenny kernel" concurrently will also be 
quite easy.

>I'm assuming also, that I could make copies of the binaries dropped into
> /boot, upgrade, and tell my boot loader to also reference the "old" files. 
> This of course assumes that modules and such are compatible in between the
> different versions (which is dubious).

You could.  Since the kernel ABI determines module compatibility, modules for 
the new kernel would work with the old one it is was not assigned a package 
name.

Kernel breakage to the point of "I can't boot" is nearly unheard of when the 
upgrade does not touch the kernel ABI or for any kernel upgrade that gets 
pushed to stable ("stable-and-a-half" or not).  So, I'm a little confused as 
to exactly what you are trying to do.
-- 
Boyd Stephen Smith Jr.                   ,= ,-_-. =.
bss@iguanasuicide.net                   ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy         `-'(. .)`-'
http://iguanasuicide.net/                    \_/

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