Re: [gentoo-alt] RFC: Slides for Computing in High Energy Physics

[Guilherme Amadio]

Hi Benda,

On Mon, Nov 04, 2019 at 12:04:25AM +0800, Benda Xu wrote:
> Dear All,
>
> I am going to give an oral presentation at the Computing in High Energy
> Physics Conference at Adelaide Australia on Tuesday:
>
>   https://indico.cern.ch/event/773049/sessions/323858/#20191105
>
> I have uploaded my slides at,
>
>   http://hep.tsinghua.edu.cn/~orv/pd/chep2019.pdf
>
>
> Note that there will be talks on Spack and Conda after mine. A
> head-to-head comparison in the session will be likely to happen.

You can see their slides ahead of time. I think they are all posted
already, in case you want to make a comparison in your talk.

>
> Comments welcome!

Here are my comments for the slides:

For the theme, I like the darker purple. See here an example from when
I first presented Portage in a group meeting here:
https://docs.google.com/presentation/d/1dYyYL4L9i4g6WibYpsJqL__dqD3w3KZmQKFkw40SanU/edit?usp=sharing
This is just a suggestion, though. Your theme is totally fine.

Slide 3:

There is a typo: maintenability -> maintainability

Slide 4:

from daily to ... -> from daily use to ...

Slide 5:

I think this is a key slide. It shows the main difference between
prefix and others, namely, that the INTERP points into EPREFIX and
makes it independent. Important points are that it doesn't require
sourcing any setup scripts to use, neither setting any variables.
You should point that out, and say that we can only do this because
of the special glibc that we build. No other package manager does
that as far as I can tell. Also, you can use the same prefix on
CVMFS for Ubuntu, CentOS, etc, instead of having one prefix per host
system. That's another great advantage that prefix has over everything
else.

Slide 6:

For CMake, it should be cmake -DCMAKE_INSTALL_PREFIX="$EPREFIX" ...

Slide 7:

Rust Carge -> Rust Cargo

I'd avoid bundling the stuff that doesn't exist yet with the ones that
already exist. Maybe it's better to put them only in the next slide
and say that it would be possible to have converters for some things.
Spack and conda seem quite unfeasible, though, so I wouldn't list those.
Spack uses python for recipes, and shares the same recipe for all versions
of a given package. See the recipe for ROOT, which was based on my ebuild:
https://github.com/spack/spack/blob/6e78730a9776e310e375fa4697aae828665af85f/var/spack/repos/builtin/packages/root/package.py
Not sure about conda, but it's more like apt/rpm, so converters are
probably not an option, or at least very hard not to make a mess, since
packages will be duplicated in both worlds.

Another thing is that spack and spack-dev are somewhat different things.
The spack-dev thing is supposed to be something to help work on package
development by creating a dev environment where you can work on the
source and use spack to install. (Think like using ebuild configure,
then work on the source, then ebuild compile/install/qmerge by hand.)

Non-exist, ... -> Do not exist yet, ...

Slide 8:

Please point to packages.gentoo.org :-) It's a great resource.  It lists
the number of packages in the front page, so you could just put a
screenshot in your slide and make it a link to the site. Same for the
categories, you can link to https://packages.gentoo.org/categories and
use a screenshot.

Not sure about what you mean with the red box (Our manifesto). It can
probably be removed.

Slide 10:

Maybe try using minted for getting syntax hilighting, and put the code
in listing boxes. I can send you examples if you want. It will look a
lot nicer!

Slide 11:

Coexistance -> Coexistence

This is also an important slide. Here there is a combinatorial build
with many different versions of everything and then "views" into the
builds are created by symlinking into the real directories, but that
has its issues, obviously. Gentoo puts all of userspace into a single
directory and stacked prefix can be used to share the base and change
the top while still keeping everything consistent when things are
updated, which is the important point to make.

Slide 12:

This is also a crucial slide, as it explains the bootstrapping process.
You can probably move it earlier, when you start explaining about
prefix and put a lot of emphasis on the fact that only the host kernel
matters, and that we can have one thing that works on any Linux distro,
as long as the kernel is recent enough. This is something only prefix
can provide at the moment, and with CVMFS, it's easy to take advantage
of this benefit.

Slide 13:

Maybe use some screenshots from Android? That would be really cool.

Slide 14:

I think that you don't need to mention other package managers in the
conclusion. Just focus on the strengths of Portage and prefix in
combination with a means of distribution like CVMFS (or any distributed
or networked filesystem). I think that it would be great to see more
adoption of Gentoo in the scientific community!

The presentation is very good overall, and I'm sure you'll do great
there presenting Gentoo.

Good luck!

Cheers,
-Guilherme