Re: A real-life test of long-term reproducibility

[zimoun <zimon.toutoune@gmail.com>]

Hi Blake,

I am late to the party. :-)

On jeu., 04 août 2022 at 15:35, blake@reproduciblemedia.com wrote:
> August 4, 2022 8:43 AM, "Konrad Hinsen" <konrad.hinsen@fastmail.net> wrote:

>> One of our claims is that Guix can rebuild code identically as long as
>> we have a machine with a Linux kernel and a POSIX filesystem.

This claim is correct, AFAIU.


> This actually isn't the claim. Reproducibility is only guaranteed on
> Guix systems. It's important that you reproduce the entire system, which
> means you will have needed to have saved the commit of your version of
> the Guix package manager in order to return to that system.

It is possible to rebuild identically on any foreign GNU/Linux distro
running the Guix package manager.  The assumptions, between the 2 points
in time, are:

 1. compatibility of the Linux kernel
 2. availability of all the source code
 3. compatibility of the hardware

AFAIK, #1 and #3 are satisfied.  About #2, it depends and many corner
cases are around.

Running Guix System would allow to easily satisfy #1, but, AFAIK, no one
reported an incompatibility of the Linux kernel defeating “guix
time-machine -- build”, and thus, it appears to me still hypothetical
(although possible on the paper) that, in this case, Guix System would
still allow the travel back in time.


> See the section of the Guix manual "Replicating Guix" for more info.
> https://guix.gnu.org/en/manual/devel/en/html_node/Replicating-Guix.html

Guix System is not mentioned, IIRC. :-)


Cheers,
simon