[systemd-devel] vt220 default for serial console still relevant?

[smcv at collabora.com]

On Sat, 11 Jul 2020 at 21:04:18 +0200, Lennart Poettering wrote:
> widely-supported TERM value

For a value of TERM to work (at all), it must be something that is reliably
present in the terminfo/termcap data visible to TUI programs.

Debian divides terminfo into two categories. It wouldn't surprise me
if other distributions have a similar split, with the line drawn in a
different place.

ncurses-base is marked as Essential (so every Debian system is required
to have it) and supports a relatively small number of common terminals:
https://packages.debian.org/sid/all/ncurses-base/filelist
(In particular this includes linux, vt220, xterm, xterm-256color, ansi,
screen and tmux.)

ncurses-term is not Essential (so it will be missing from minimal
systems), and contains the complete menagerie, including many historical
serial terminals.

> stick to a reasonably powerful subset

It might be useful to observe that there are two possible levels
of compliance with particular terminal escape codes: "does the right
thing" and "doesn't do the wrong thing". My understanding is that the
ANSI terminal spec is sufficiently general that a terminal emulator can
gracefully degrade by treating certain equivalence classes of terminal
escape as "do nothing", for example accepting but ignoring colours.

    smcv