Improve and update Windows specific platform instructions

[musm]

Note I accidentally committed this to master and subsequently reverted the commit, apologies for that.

[musm]

closes JuliaLang/julia#7267

[tlienart]

Cool 👍

[PallHaraldsson]

Note, the 32-bit Julia binaries work on both 32-bit and 64-bit Windows

Maybe a similar problem exists on Windows, as with with the julia snap (on Ubuntu), that I discovered is 32-bit. It does and should work, until using with 64-bit libraries, e.g. with PyCall.jl. 'm not using Windows so I can't test. I guess if you install 32-bit everything else it would work (also on Ubuntu, just not commonly done).

[zlatanvasovic]

@PallHaraldsson Did you try just sudo apt install julia? It's maintained by Debian developers and it's up to date.

[PallHaraldsson]

No, and not it isn't(?). I'm not saying I have a problem, only had, a pitfall for others, and maybe on Windows.

I did:

$ sudo snap install julia --classic

it works, except 32-bit, so works until it doesn't, but for me at least on Ubuntu 18.04.4 LTS:

$ sudo apt install julia
[..]
Package julia is not available, but is referred to by another package.
[..]
E: Package 'julia' has no installation candidate

I don't have a problem, I use the download page.

[zlatanvasovic]

The package exists for 20.04, 19.10 and 16.04. Maybe that's why you can't find it? I use 20.04 and it works out of the box.

[PallHaraldsson]

Like I said, I do no have a problem, and actually use Julia 1.6. Still good to know, and strange 18.04.x isn't supported. Maybe an oversight/bug since older 16.04 is? [Ironically I get "upgrade offer to 19.10, which will soon expire, so I wait, as I know offer to 20.04 will come soon, and I'm not in a hurry.]

I tried to find info on and found:

https://askubuntu.com/questions/842042/problems-installing-julia-language

and link there to:

https://julialang.org/downloads/platform.html

we might want to resurrect that page, or redirect to some other.

I didn't know promoted, and a little regrettable with the 32-bit problems:
https://ubuntu.com/blog/julia-and-jeff-discover-the-ease-of-snaps-at-the-snapcraft-summit

“Snaps seemed like exactly the answer as it lets us use whatever dependencies we need. It’s a perfect distribution mechanism for us,” Jeff states.

[EDIT: I see now 64-bit "amd64" support at "Show architecture" drop down box (not sure it's an option) for that snap, just not sure why I get 32-bit "i686-pc-linux-gnu"; it's still however only 1.0.4. It should be upgraded to 1.0.5 at least, just not sure if 1.4 or soon 1.5 is appropriate.]