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Re: Re-evaluating architecture inclusion in unstable/experimental




Hi Philipp!

On 10/3/18 4:29 PM, Philipp Kern wrote:
> Please excuse my ignorance, but which architecture do we still have with
> 2 GiB address space? The main point of removing s390 was that this was
> unsustainable.

The 32-bit MIPS architectures have this limitation which causes various
build issues up to the point that maintainers have to reduce optimization
levels for the C/C++ compiler to be able to build a package. Another issue
is that the Rust compiler, despite being fully supported on 32-bit MIPS,
cannot be built natively there because the build process runs out of
memory at some point.

>> I have seen IBM people on multiple occasions in various upstream
>> projects trying to remove code for older POWER targets because
>> they insisted anything below POWER8 is not supported anymore. In
>> some cases like Golang with success [1].
> 
> Yeah, IBM behavior has been incredibly frustrating here on the System z
> side, too. Essentially they end up actively removing support for
> anything they don't support anymore.

Somewhat relieves me to hear that I'm not the only one running into
this problem. I find it frustrating though since it leaves a bad
impression on what attitude IBM has towards open source and the
community.

> To some degree I understand this behavior: It's a real relieve to not
> need to support something old and crufty when you're the engineer on the
> other side having to do that. Even when such support is contributed,
> someone needs to keep it working and they won't keep old hardware around
> for that.

Sure, I understand that. But in the case of Golang, the necessary extra
code paths are really manageable. In fact, have my own tree of Golang
where I reverted the changes which dropped POWER5 support and I keep
rebasing this tree from time to time and it still works fine.

It does work without problems on the x86 side with the kernel and the
toolchain still supporting rather old hardware. POWER5 isn't that old.

> But it has very awkward implications on the people that still have that
> hardware for one reason or another and don't actually rely on a support
> contract.

My main argument is that if there are still a reasonable amount of users
and there are still enough people to help maintain a port, it should
not removed just because it's old. In the end, software is written to be
useful to users and not for the sake of the people writing it.

> For s390x I can say that the port was driven without any commercial
> interest on both Aurelien's and my side
The question is though: Is there quantifiable amount of users that is
running Debian on such big iron instead of one of the Linux enterprise
distributions on the market? If the argument is about maintenance burden,
then does it justify to support Debian on s390x when the number of users
is small? And, if yes, why does that not apply to ppc64, for example?
(I would mention sparc64 here as well, but there is actually a valid
 blocker which is the lack of supply of new hardware for DSA).

Thanks for the insight!

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@xxxxxxxxxx
`. `'   Freie Universitaet Berlin - glaubitz@xxxxxxxxxxxxxxxxxxx
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