Quoting golinux@??? (golinux@???):

> OK. Having no idea what an S/390 system is (except for a scan of
> the wikipedia page), I'm hoping that someone can 'splain how this
> will affect community based Linux and everyone who jumped on the
> systemd bandwagon:

It's a jackassical attempt at humor, as others have said.

IBM System 390 was a 1990s series of models of what used to be called
mainframes (though now _way_ smaller than they used to be), with their
own chip architure. It was replaced in the 2000s by the IBM zSeries family
(which then got other similar names with 'Z' in them, whenever IBM
Marketing department got twitchy and decided to rebrand a little).

zSeries is 64-bit, and I vaguely recall that being one difference from
the related S/390 series that preceded it, but they're closely related.
The Linux relevance is that there have for a very long time been ports
to S/390 boxen and to zSystems, including an official Debian port that
as of Debian 9 'strech' drops the 32-bit 'ESA/390 mode' support and
requires support of 'Z/Architecture', which AFAIK is mostly or entirely
about that type of 64-bit operation.

(I'm vague on the fine details of these, and if someone on Dng really
thinks it's worth time gnawing on fine details that I've failed to cover
with excruciating exactitude, about which I could not possibly be arsed
to research fully, you'll earn a virtual cookie and a vitual pat on your
little OCD head.)