Re: [Qemu-devel] [PATCH] hw/i386: Deprecate the machines pc-0.10 to pc-0.15

[Markus Armbruster <armbru@redhat.com>]

Thomas Huth <thuth@redhat.com> writes:

> On 10.05.2017 11:08, Daniel P. Berrange wrote:
>> On Wed, May 10, 2017 at 08:48:53AM +0200, Thomas Huth wrote:
[...]
>> Also unless we're going to get more serious about automated testing to
>> validate machine type compatibility between *all* previously releases,
>> I think that 6 years / 18 releases is too long a time to have any
>> confidence in migration compatibility between versions.

Seconded.

> Distro vendors often offer 5 - 10 years support for certain versions of
> their Linux distros, so I think we should at least support 5 years, too.

Non sequitur.

Distro vendors put in serious work to keep versions working for 5 - 10
years.  We can't, and we don't.  All we do is try not to break things,
which is nice, and helps the distro vendors some, but a far cry from
anything I'd dare call "support".

Perhaps an argument could be made that us keeping to try for at least 5
years would help distro vendors enough to be worthwhile.  Maybe, but
color me skeptic.

>> IOW, I think you should be more aggressive in culling old machine types
>> that this patch is...
>
> Actually, I like the idea of using the major release versions for
> defining the set of removal - hoping that we will do a v3.0 next year
> which then would support the previous two major release versions 1.x and
> 2.x, but drops support for the 0.xx versions completely ...

I wouldn't put *that* much weight into our past version numbers.  If I
remember correctly, there was no more to 1.0 than a feeling of "this 0.x
thing is getting ridiculous".