:: Re: [DNG] Beowulf: 32bit or 64 bit?
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Lähettäjä: Adam Borowski
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Vastaanottaja: dng
Aihe: Re: [DNG] Beowulf: 32bit or 64 bit?
On Thu, Nov 26, 2020 at 01:12:01PM +1100, wirelessduck--- via Dng wrote:
> > On 26 Nov 2020, at 13:02, Gregory Nowak <greg@???> wrote:
> > <FEFF>On Wed, Nov 25, 2020 at 05:34:16PM -0700, Fred wrote:

    ^^^^^^
Unrelated: Gregory, please fix your mail client to not insert invalid
control characters.


> >> I think Debian Jessie is 32 bit. To upgrade to Beowulf I just followed
> >> instructions that didn't say anything about 32 or 64. I just assumed
> >> Beowulf was 64 bit.
> >
> > Debian jessie was available in i386 and amd64 as far as I recall.
> >>
> >> My CPU appears to be able to do 64 so how do I change over?


You really, really want to use a 64-bit kernel even with 32-bit userspace.
Doing otherwise is insecure and very slow. Especially with mitigations for
bugs found in the last few years. 32-bit kernels can't do so right, and
their code to handle modern hardware is really barebones and slow -- and
Linus refuses to merge speed-ups that would complicate things, as 32-bit
kernels are meant only for 32-bit hardware.

You need to install an -amd64 kernel. If that AppImage is self-contained,
that's all.

If it won't work, please add minimal multiarch:
    dpkg --add-architecture amd64
    apt update
    apt install libc6:amd64


> > Probably the easiest way is to do a fresh 64 bit install of
> > Beowulf. There might be a way to do a migration through dpkg
> > --add-architecture, but I'm not sure about that.
>
> The debian wiki has an article on doing this transition.
> https://wiki.debian.org/CrossGrading
>
> It also mentions a new package debian-crossgrading from google summer of code 2020 that appears to automate some of this.
> https://salsa.debian.org/crossgrading-team/debian-crossgrading


If you feel adventureous (or have good backups, or would do a fresh install)
it would be nice if you could give "crossgrader" a try. Its author would
be thankful for feedback, including problems you face.

That package should be available in ceres and unstable.


Meow!
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